Starting Seeds Indoors: Tips and Trials, by CAL

Last year I began to get much more serious about starting my plants from seed. As my garden has grown in size each year, I saw the wisdom in starting my own seeds. Never mind the increased pressure to make sure we have a sustainable food source during these turbulent times. I reasoned that starting my own seeds would give me a jump on the growing season. I could control for erratic early season weather and I would save a great deal of money as the price of seedlings as the nursery has been doubling in price. I have been expanding my growing space in order to increase the amount that we eat from the garden versus need to buy from stores.

With the shutdowns and food scarcity issues, the popularity of growing your own garden has increased greatly. So just finding the seedlings you want to grow is more than a little difficult. I cannot find many heirloom seedlings grown in organic soils at our local nurseries. In fact, one of the more popular organic nurseries locally was shut down for much of the spring this last year. And lastly, starting your seeds indoors when possible may address some of the changes in our weather we are seeing as the Grand Solar Minimum continues to impact our growing season.

My hope is that if I can have healthy, strong seedlings that have begun in a controlled environment, they will have a better chance of dealing with weather variations that might occur in May and June in our local area. For instance, too much or too little rain, late frost dates, and colder than normal temperatures all may occur. Stronger plants may tolerate these variations better when it comes to planting time. Only time till prove me right or prove me wrong. Nevertheless, these are my excuses for investing in seed growing equipment and so far, my spouse is in agreement with my plan.

I have an abundance of windows in my home which face both east and west. So last year I purchased sterile potting mix and filled 72 cell seed containers. I then proceeded to move these containers from my east windows for early morning light to my west windows for late afternoon sun. I did so on a daily basis to maximize the light. I did not add any amendments to the soil or extra light. My plants got lots of daily care and nurturing but nothing else. Well, I did end up with lots of seedlings, but they were leggy, started too soon to plant into my garden and I lost many of the seedlings. In the end, I did not achieve any jump on the growing season. In fact, I delayed it as many of my plants experienced transplant shock and it took even longer before they began producing, if they did at all.

This year I have a new plan. First, I did my research much more thoroughly. I am going to list the key information that I will be implementing this year and some of the resources that I am relying on for this year’s growing plan.

The basic needs for germinating seeds are warmth, light, and some moisture. That sounds simple, right?


I’ve purchased my heirloom seeds from a variety of locations including Baker Creek, Bountiful Gardens, and Territorial Seed just to mention a few. I prefer to use heirloom varieties from companies like these. We try and grow organically whenever we can, and we are interested in producing vegetables and fruits with a much broader varietal array than what you might find in a grocery store.

As I look into the future growing years, the information on the Grand Solar Minimum suggests dryer weather and colder temperatures for my growing area. I am trying to keep this information in mind as I select various seeds. Territorial Seed is located near my home so I will be germinating seeds that are adapted to the Willamette Valley where I live. Many resources emphasize the benefit of using seeds adapted to your particular climate and soil type. This does not preclude using seeds from other locations, but it may give you a year or two quicker adaptation and thus more production from your plants. Deep South Homestead (Danny and Wanda) talk extensively on their YouTube channel about how they are adapting their seeds (potatoes and English Peas) to their climate and soil. YouTuber MI Gardener also discusses the differences in production when you use seeds that are appropriate for your local growing conditions.

Growing medium

It is important to use sterile potting soil to start your seeds. This eliminates contaminants that can impact seed starting and growth. Baker Creek recommends a peat and perlite potting mix. They add 1 pound of gypsum to their mix to provide nutrients to the soil and an ounce or so of Dawn dish soap to address water absorption of the soil. The soap moderates the amount of moisture that the soil takes up so that there is neither too much nor too little, according to Baker Creek.


Many seeds require heat in order to germinate. Heat mats can provide this heat, or you can locate a warm location in your house. The top of a refrigerator has been mentioned as one spot that is warm enough to germinate seeds. I’ve purchased several heat mats on Amazon. The price ranges with the size of the mat and ranges from roughly $30 for 17 x 20” mat up to $60-95 for larger mats. Of course, the more functions the mat is able to do such as being able to set a precise temperature will correlate with the price.

Seeds such pepper plant seeds like it warm. Baker Creek sets their mats at 80 degrees for peppers and 75 degrees for most other seeds in their greenhouse seed starting location. My mats will be located on steel racks in the corner of my rec room. This room is not normally that warm, so I am hoping to set my mats for 70-75 degrees for most seeds. I’ll boost them to 80 degrees for my peppers.


The benefit of proper light is that your plants do not become “leggy.” Proper light allows the photosynthesis process to occur and results in strong plants with healthy green leaves that produce well. Leggy plants may or may not survive a transplant and require many more weeks to establish and produce, if they do at all. Do not consider using a north-facing window to start your seeds as your plants will not receive enough light to grow properly.

When starting your seeds indoors you need to plan for your plants to have 4 to 6 hours of direct sun or you can purchase grow lights that will provide a minimum of 5,000 lumens and at least 5,000 Kelvin. Lumens are the light energy given off by the light and Kelvin is temperature — with the correlated color spectrum that the lights produce. If your grow light only gives off 2,500 lumens, then you can put two tubes or lights together to achieve 5,000 lumens. The greater lumens given off equates to the height that a light must be suspended above your plants.

The MI Gardener gives the following data to help you plan where to hang your lights:

Lumens                             Height Above Seedlings

< 5,000                               3 – 4     inches

5,000-9,000                       5 – 7     inches

10,000                                10 – 12 inches

30,000-40,000                    5 – 6    feet


Kelvin is the thermodynamic unit of measure of the color spectrum that your grow light gives off. 6,500 Kelvin is equivalent to blue light or full sunlight. You need a minimum of 5,000 Kelvin to approximate the sunlight your plants will require. My grow lights have two phases. The first is a blue light or seed germination switch that provides more of the blue light spectrum. As the seeds germinate into small seedlings, I have a second switch that provides more of the red light in combination with a blue light. These lights are not the more expensive lights on the market so I will have to see how the lights do over time and whether the two-phase lighting makes a difference.

The biggest mistakes gardeners make when starting seeds, according to several sources, are the following:

  1. Inadequate space for seed growth. 3-inch cells are a better choice than those  72-cell containers with 1-inch square cells. We think we need lots of seedlings when in fact we need to allow those seedlings that we are growing enough space to establish good root and plant growth. So, more is not necessarily better. Think quality over quantity.
  2. Placing the seeds/seedlings too far away from the light source. The further away we have the plants, the greater chance that the photons produced by the light miss the leaves of the plants. Check your lumen output and hang your lights accordingly.
  3. Starting seeds too early. Don’t let your excitement for spring growing get you started before you should. Identify the last frost day for your area and then look on the back of your seed packages for recommended seed starting time frames. If the packet recommends starting your seeds 5-6 weeks before your last frost, take a calendar and count back 5 to 6 weeks and plant your seeds at that time. I took all of the seed packets I plan to grow this year and set up a spreadsheet on the computer with planting recommendations and the date to start the seeds. You can round to the week to make it easier and then pick a day each week to start your seeds. When I did this, it was obvious that I started my seeds too early last year. You do not want your seedlings to outgrow your containers or even worse begin to bloom at this stage. If this happens it is likely that the blooms will drop off during transplant as I experienced last year.
  4. Start the right seeds indoors. Root vegetables can be started outdoors before the last frost. There is no need to start these seeds indoors as they do not fare well during transplanting. Vegetables such as radishes, carrots, arugula, and scallions can tolerate a light frost. I am in Zone 7 and my last frost date is approximately May 15th. Typically, we can have a heavy frost or some snow in the Willamette Valley in February as we saw in some locations this past week. I plan to start my root vegetables in early March outdoors when we don’t often see a heavy frost. I’ll use row cover if there is a prediction of a heavier frost. Peas will tolerate cold rainy temperatures so they can be directly planted here in March. Corn requires warm temperature and is a seed that does better when planted directly into the soil rather than starting indoors. Check your seed packages for recommendations on whether to start your seed indoors or outdoors.

We will see how well I do this year. However I already know that given the limited availability of many items this spring I will be ahead of the pack.

Don’t be afraid to give seed starting a try.


  1. You’re still going to have leggy seedlings if you put your trays next to a window for sunlight. Modern glass has UV inhibitors designed to block the bleaching effects of direct sunlight, just the stuff that your plants need.

    In addition, you need to get the air circulating around your seedlings, not blowing on them but enough to be an occasional gentle breeze. The way it was explained to me, the movement of the plant from the breeze causes microtears on the stem, which are then repaired to rebuild the stem straighter and stronger. If you don’t have any air movement your plants will fall over.

    A small oscillating fan placed well back to minimize the direct air impact will do what you need to make stronger plants.

    1. Clear glass does not block UV light, or not much. It is also the cheapest option when buying windows.

      Clear glass also helps sterilize the environment, reducing viruses and bacteria.

      UV does fade furniture, which is partially why I chose a light beige upholstery. Only direct sunlight does color damage; indirect sunlight is fine.

    2. RayK, good explanation about the plant stems. I have friends who simply brush a hand across the leaves every time they pass the plants.

      Also, be alert when using any heat source (I use a simple 100 watt bulb) to check the soil moisture religiously. I lost one entire early planting of tomatoes due to my inattention. Sigh.

      Plain old flourescent tubes are cheaper than grow lights and have worked for me since 1982.

      Carry on

  2. Nice essay! Danny and Wanda are a stitch to listen to. I’ve gotten some good ideas from them.

    I have one of those cheap $20 shelving units that has the plastic zip cover over it, which I’ve adapted for seedlings. It’s light weight so it can be moved around and covered up to keep heat inside. I attached the grow lights to the underside of each shelf. But, I had trouble with ‘leggy’ seedlings due to the distance between the light and seeds. I
    moved the seeds closer to the grow lights, which did help.

    Since I keep my house at 69 degrees, keeping the seeds warm is a problem. The warming mats have trouble keeping the trays warm enough for some types of seeds. I keep trying different things but so far just putting a flannel throw over the shelving unit seems to help. Ideas are welcome here.

    Once the seedlings are strong enough we move them to the hoop house where they stay until mid April when they go into the ground.

    1. My seedling rack has 2″ of EPS insulation on the base and sides. I have an insulated blanket to cover the top at night when the growlamps are off. I use a warming mat designed for car batteries rather than horticultural mats, which has about double the power per unit area of the horticultural ones. It sits in a slight trough made of 1/2″ ply base and thin 1/2″ sides that the seedling trays sit on, as the battery warming mat isn’t designed to take the weight of the trays. The seedling trays are in fact shallow boot trays filled with beach sand, which provide a reservoir of both heat energy and water for the seedling cells, whilst also protecting the warming mat from any water. Essentially, the mat heats the sand and the sand heats the seedlings. This has a buffer effect protecting the seedlings from the cycling on and off of the warming mat. My system is microprocessor controlled as it’s in an unheated room, but if yours is in a constant temperature room then it shouldn’t take too much experimentation to have the mat running off a mechanical timer that switches it on for x minutes each hour: Solve for x 😉
      The mat does double duty as it is used for warming my truck battery in my unheated barn in midwinter, and shifts to the seedling grower in March. As a further tip, the mat works great wrapped round a tub of roofing cement to keep the cement workable if you find yourself having to do any roofing work in cold weather. The boot trays are also used during winter for their intended purpose.

    2. Animal House I put a dark curtain around the shelving unit so you don’t look directly at the grow lights when you are in the same room. I don’t know how much heat retention they will provide. I’ll keep an eye on them.

  3. I appreciate your research. I believe with things changing as they are it’s important to start growing your food if possible. Even if you grow in containers. For years I started my seedlings in a south facing window up here in N.W. Montana. With just the natural light they did get leggy but honestly I still got good harvests. I did run my hand over the seedlings ever day or so to toughen them up. It’s important to harden them off before you set them out in the garden permanently. Leggy tomato plants can be planted deeply in the soil with just a few leaves sticking out. This is actually a good thing and encourages more root growth. It is important for the plants to grow in a warm area. Because of this we’re changing where we start ours this year. The room we had them in last year ended up being too cool for some of our seedlings and they took a long time to develop. Mats and lights are great but it is usually possible to start seedlings without them. The advantage of overhead lights is you’re not dependent on sunlight. With a little resourcefulness most anyone can start seedlings. Plus, I just love watching those little plants pop up and grow.. It’s amazing how these little tiny seeds can produce huge plants that grow so much food! It’s a miracle in the making.

    1. I just ran my hand over the seedlings. What a simple and easy way to help strengthen them. Thank you Sis for the tip. I’m adding it to my daily care routine.

  4. Great article, CAL!
    It’s always in this time of year that we begin to THINK SPRING. Can’t help it!

    A couple of follow up thoughts to your article…

    * We have found that the heat mats are very helpful. This is the first year we’ve used heat mats, and the results have been excellent. Although our success rate has been high, we will probably place ceramic tiles under the heat mats for some modest “thermal mass”. Given the that temperature is digitally regulated, we’re not sure this will accomplish a whole lot, but we’ll give the experiment a go to see where it takes us. The suggestion from Animal House about the use of flannel was really quite good. It’s simple, affordable, and low-tech — all great qualities!

    * In a future without electricity, I wonder about the use of “black barrels” as heat syncs for seed starting trays. Something to consider!

    * Speaking of the future. You’re wise to consider the likelihood of changing (and colder) conditions. In the strategies, be sure to consider the risks associated with cloud cover for extended periods of time (think active volcanoes or nuclear winter effects), shorter growing seasons, and extreme cold that will require significant mitigation.

    * In our strategy, we use either the 72-cell planters or the larger pots depending on the plant, relative germination rate (or likelihood of germination success), whether or not the particular plant can be readily transplanted, etc. Both work well for us, although I do see the appeal of starting with the larger planters and staying with those too.

    * Your experimentation with varieties is critically important. Find those that grow well for you, be aware of varieties that might make good alternatives should conditions change, and specialize in several garden crops that provide solid nutrition, flavor variety, and foods that are good both for fresh use and are storable in some form.

    * Explore complimentary strategies including “sprouting”. It’s easy and fun. Just be sure you’re properly soaking, rinsing and draining properly. Food safety is #1. The results are delicious additions to salads and sandwiches. Mike Adams, the Health Ranger (and at Natural News) has a great sprouting video.

    * We encourage everyone to grow in-ground, in raised beds, in a greenhouse, hydroponically, and vertically. Gardening for literal survival takes practice, and time to develop infrastructure. Don’t give up! Just get started.

    1. TofA, * In a future without electricity, I wonder about the use of “black barrels” as heat syncs for seed starting trays. Something to consider! That is an idea I hadn’t considered. In the past, I juust started seeds a couple weeks earlier and let them grow slo-o-wly. I reckon that is how our electricity-free ancestors did it.

      And you end with, “Gardening for literal survival takes practice, and time to develop infrastructure. Don’t give up! Just get started.”

      Big Amen.

      Carry on

      1. We were absolutely “ruined” as gardeners when we discovered we could plant our zucchini starts early, get them outside early, protect them from frosts, and start harvesting squash early.

        Of course we are not only spoiled by the early production of garden goodies, we also look at this from a survival standpoint. If we can extend our growing season, we improve the likelihood that we can grow enough food to sustain ourselves and hope as well to have enough to freeze or can.

        We’ve got a spot set aside for black barrels inside the greenhouse, and plans for a passive solar convention heating system. No electricity. Low tech. We think it should be very effective, and are adding this to our heat-retention strategies.

        Hope and pray that everyone will garden with great success this year and every year. This is an excellent subject for our conversational group. There are many gardeners among us, and we all like to share what we know — and discover new ideas too!

      2. Once a Marine, =

        A ~passive Solar Greenhouse is one idea for extending the growing season.

        Chinese Design for Passive Solar Greenhouse Backyardriches site.

        “In northern China, solar passive commercial greenhouses cover over 1.8 million acres. These greenhouses typically use no supplemental lighting, and little or no heating, to produce vegetables from Fall through Spring. It’s a highly evolved and very commercially successful design, and virtually unknown in North America.

        One of the central design precepts of the greenhouse is a high volume to surface area ratio, which ensures a large interior thermal mass in the soil, air and back walls relative to the surface area of the glazing. At the end of a day of Winter sunlight you close the thermal blankets and the internal large volume of thermal mass efficiently retains the sun’s heat.”

        This type of design with pictures are elsewhere on the Web. The idea is actually a type of design, that goes back years previously in the colder areas of the world. The design is for a large commercial or multi-family greenhouse.
        Contraryfarmer site. Building Horse Manure Hotbeds
        July 23, 2008 · Practical Skills Series

        “A hundred years ago, hotbeds were used profitably near large cities to grow two crops of lettuce through winter, and then a crop of bedding plants for setting on in the garden in spring. As long as horse manure was available, and of course it was in great quantities, these hotbeds produced lettuce at the rate of forty to fifty heads per 3 by 6-foot bed at far less cost than it takes today to ship lettuce from warm-winter states or raise it in greenhouses. Farmers near such cities as Boston and New York operated as many as a thousand beds, providing jobs for many people and making a good profit, with the expenditure of very little fossil fuel.

        The details of the design of a hotbed for practical winter use are seldom given in modern books, but they should be incorporated into any hotbed, even if used only for starting plants in spring, and even if an electric cable, rather than horse manure, is used for heat. But where horse manure is available, one can avoid the out-of-pocket cost of cable and electricity. This savings can be especially significant if one uses the hotbed all through the cold winter months. The cost savings is only part of it. Manure will also provide fertilizer for the hotbed plants and finished compost for the garden after its heat cycle has passed.

        But whatever you use for your source of heat, a good hotbed should satisfy the four following requirements:” …

        … “Only horse manure is practical for hotbedding. Not only is it more available in quantity, but it heats up quicker and hotter than most other manures. The less straw or other bedding in it, the better, but mixed manure and bedding is adequate. The trick is to start the manure heating only just before you want to put it in the hotbed. This is easy if you have your own horse or access to a stable.” ….

        Manure hotbeds are just one of the many reasons, people left the bucolic country life, for the rat-race in a city.
        House Flies everywhere too with Horse manure and Chicken manure around. +Being bit by a big Horsefly hurts, and draws blood (from people). [Yes, indeed it does.]
        +Horse hide is thick, while still on a horse, but a big Horsefly can make a horse jump!
        19 Ways to Heat Your Greenhouse ~ at, Sunoven site.
        Just might spark an idea or two. (Maybe 19 ideas!)

        Very famous President Harry Truman joke for the oldsters.

        “Harry Truman, when he was U.S President, once addressed the Washington Garden Club and kept referring to ‘good manure’ that must be used on flowers. Some society ladies complained (later) to the First Lady Margaret Truman, “Bess, can’t you get the President to say fertilizer instead of manure?”

        “The First Lady replied, “Heavens, it took me 25 years to get him to say ‘manure’.”
        [Found all over the Internet; This copied from a site, that wants your email.]

    2. Great ideas TofA. I will be most interested to see how your tile work as a thermal mass. I’ve been keeping a journal that includes when ip,an, the planting container, height of the light etc. I love each suggestion. Additional heat may be necessary so I’ll need to look at my options.

      We do use sprouting as a supplement for salads and sandwiches. I just picked up a few more packs this morning when I was out doing errands. They are easy to grow and taste great.

      1. Enjoy those sprouts, and keep that journal going! We always think we’ll remember, but there are sooooo many details. This is sure to improve your success rate. Thanks so much for the contribution of this article, and the opportunity for such a great conversation among the group. You are among kindred gardening spirits!

  5. Nice article and quite timely I might add.

    Good morning all.
    I have a question, has anyone here used/experimented with winter sowing? As in sowing seeds in lidded containers, setting them outside and letting them germinate au natural?

    While I will be starting seeds with the usual racks, lights, mats, etc. I want to figure out how to start seeds without all that….you know, in case China decides to turn off our lights for non payment. : )

    1. Hey TeresaSue I have a relative in the Redoubt trying au naturel this year with every crop inside of milk cartons cut in half and then the top half put back on once the seeds are sown. They sent me a photo a few weeks ago of the cartons all lined up in the garden. I can wait to get their data. 🙂

      I don’t plant a lot of my flowers each year because they come back from seeds and are typically larger that the transplant ones available at the stores that same time of year. Ditto on squash and I let the volunteers grow wherever they come up. After noticing volunteer poppies coming up year after year in front of the post office, I planted mine in a grow box a month ago to see what their natural germination date is, then I’ll transplant them. Luffa sponge is another very long-season crop so I’ll get some planted both in and out of the garden, in another month or so (after the single-digit temperatures are no longer a threat) to let them germinate when they want, then I’ll plant more when I normally do. That’s one more thing I love about heritage seeds, I end up with so many at harvest time I can plant them all over the place without having to worry about “wasting” them or having experiments fail.

      1. Now that is an interesting thought, to plant seeds “earlier in a season” to see when they would choose to germinate in the spring…

        Hmmm! Some would rot, but not all. Something to think about.

      2. St Funogas that’s how I’m planting mine and I live in the Redoubt. : )
        I went ahead and planted my poppy seeds a few days ago, I just sprinkled it on top of the snow, I’ll let you know how it does. It’s a beautiful poppy, the seeds given to years ago from a friend. I call them sky blue pink as I have no idea what cultivar they are. They are the most enchanting pink with a blue-ish/purple center. They are so pretty with hollyhocks.
        They make a ton of seeds too and reseed themselves quite nicely.

      3. My volunteer squash usually do better than what I plant by hand. The same is usually true for volunteer tomatoes as well. Actually, I use a shovel to carefully “transplant” any volunteers into a straight row of any volunteer that I want to save. I just dig out a spot the size of a shovel full of soil where I want to plant to be and then “excavate” the volunteer in a shovelful of soil with the plant and then move it to the hole I previously made for it. Most of my “instant transplanting” volunteers survive if I’m careful.

    2. Plants naturally engage in winter sowing. They drop their seeds in autumn, the seeds that survive the winter sprout in the spring.

      We humans like to have more control than that, so we carefully save seeds and plant flats. Chuckle.

      I had dozens of kale plants come up from dropped seeds last spring. Made many local friends by giving them away. However, it is out of my control, so we’ll see what appears this year.

      Carry on

  6. As an engineer Kelvin is strictly temperature. It is a one to one correlation to Celsius. Both scales don’t start at the same point. Celsius starts at freezing of water (0 degrees). Kelvin starts at the freezing of all matter in the universe (at 0 degrees K no molecule moves) at -273.15 degrees Celsius.

  7. Hey CAL, excellent article.

    This is the year I’m finally going to get it all put on a spreadsheet like you do. I especially want to have a comments column to help me remember that the tomatoes got planted too early, too late, etc. I keep lots of records don’t always remember to check them like I should. For those with room, it also helps to plant seeds in stages to see which timing is best for future reference.

    For those of us who lack the heating/lighting materials or have windows facing the wrong direction, I have a long enough growing season that I can start most of my seedlings on my back deck with chicken wire arched over them to keep the chickens and birds away. Tomatoes are about the only thing I have enough room for starting indoors.

    My potato plants all dry up by July 7th so this year I’m going to plant them in stages instead of just on St. Patrick’s day to see how early I can plant them so I have a longer growing season. Again, records are very important for any type of experimentation.

    One more thing, I had a hail storm one year early in the season that wiped out half my tomato plants. Tomatoes are super easy to root from branch tips so I did that and was still able to have a good tomato season.

    1. “ My potato plants all dry up by July 7th so this year I’m going to plant them in stages instead of just on St. Patrick’s day to see how early I can plant them so I have a longer growing season. Again, records are very important for any type of experimentation.”

      St Funogas I understand the British plant potatoes in three batches, First Earlies, Second Earlies, and Main Crop. At least according to a blogger/gardener who lives on the Isle of Man that I enjoy.

    2. St Funogas I too have a dry spell mid summer in NH so I use tarps and IBC totes to store my extra Spring rain water for the dry spell. Good to know your areas first and last frost as well as the average rain fall for each month. An inch of rain falling fast generally runs mostly off your property but fills a IBC really fast. Placing the IBS for gravity feed to your garden and a hose bib your Well will THANK you.

      If you remember to protect the IBC from freezing (simply drain it) and from Sunshine you can get decades of use from it. Keeping a tarp over it also reduces the algae growth.

    3. St Funogas. I’ve been thinking similarly in terms of seeing how early I can get potatoes in the ground. I’m going to plant a row in one of my raised beds and put extra mulch like straw on top. We’ll see what happens.

  8. I’ve been using a couple old water bed (remember them?) heaters as heat mats for years. They still sell them new but there are a lot of used ones kickin’ around on ebay. .

  9. My home is usually too cold, drafty and dry to get good germination rates. So I bought a single heat mat, big enough for one 1020 tray. I cobbled together wire shelving/wooden blocks to make space to accomodate 3 trays stacked vertically over the heat mat. Over the top of this stack of heat mat and trays, I slide a just-big-enough cardboard box down over the whole thing. The seeds don’t need light to germinate but do need a constant warmth and humidity – the cardboard box provides both. I push a thermometer probe through the cardboard to keep an eye on the temp. Depending on the box, mat, etc., slightly differing temperatures can occur at the bottom of the box vs. the top.

  10. Good tips, thanks, good to have a list of tings to do.

    BTW, I’ve successfully used ordinary home heating pads as heat mats, without the cloth covering. No problems with moisture dirt, or leaving them on for months etc.

  11. I used the clear plastic containers found at walmart for a small gren house and my tomato plants have already started only a week later. I used an old punch heated red with a torch to burn drain and heat escape holes top and bottom. Not bad for 6 dollars. Of course it’ll still be a month before planting but I chose the tallest clear tote I could find…not sure why I didn’t think of it sooner…much easier to use and move than my other cold frame.

      1. I used the 27 qt sterlite totes. I have gotten good results from seeds for tomatoes, herbs, and flowers. Just make sure they don’t get too hot in the sun. Once they germinate, back off some on the sun some as they will scorch if left out too long since the tote is clear…make sure you get the one with the clear body and lid. The reason I get the tall ones is so the plants can get taller aND not be blocked by the lid if the weather turns nasty. Let me know if you can how they turn out if you try it.

  12. Excellent article! Thanks!

    My first potato planting of the year is done in buckets, kept indoors. The buckets have 3/8″ holes drilled in them for the excess water to escape. This bucket is placed in a bucket (without holes) to capture the water that escapes. The top buckets are filled with 2″ of soil, 3 eyes per bucket, then topped with 1″ of soil. As the plant grows, I continually fill the buckets with soil. I’ll add until I get to about an inch from the top rim. When watering, simply use the captured water for recycling. As far as lighting: I use a 4′ florescent light, no problems.

    My process takes about 9 to 11 weeks. The sizes range from baby sized to medium. Average a dozen potatoes per bucket. As soon as they are harvested, I’ll start my second batch of taters; however, it’ll be warm enough to keep them outdoors. After those harvest, I’ll repeat the cycle one more time.

    Next weekend, I’m going to try bucket carrots for the first time ever. Keeping my fingers crossed! 🙂

  13. I don’t remember if I mentioned this before but we tried the hot manure idea years ago. We dug down about 3 1/2-4 feet down. My husband the made a frame around it that he attached a large window to using hinges so we could lift it up. We placed a good layer of chicken manure on the bottom and then a generous layer of regular garden dirt ( you don’t want the roots to get to the hot manure right away) we then planted in it. At night we covered it with an old sleeping bag to keep the warmth in. Things were going just great and the plants were coming up nicely. But then our dogs found the Warm bed and decided it was a good place to sleep at night ! So the sleeping bag was pulled off and eventually the glass was broken. So lesson learned. Place bed in a protected area, fenced maybe?) and also you might make a plan for your heat retainer ( the sleeping bag in our case) to be kept dry. It was working though , and we’re here in N.W. Montana. In New York they used to have large growing gardens that were heated my manure. They had these large glass bells that they placed over the plants to keep the warmth in and still allow the sunshine through. Very effective.

  14. Some personal seed-starting observations from zone 4/5
    I have been growing/using heirloom seeds for a very long time. We are off-grid on solar power, so heat mats and grow lights are out of the question. 325 days last year without the generator starting.

    Tomato seedlings “love” to be transplanted, so I always use the one inch cubes for them.

    Ditto for peppers, although not quite as well as the tomatoes.

    The fireplace mantle is my go to spot to germinate peppers and tomatoes. They love it, but the peppers are touchy if left in that heat even two days after they are up.

    Broccoli does not transplant well so I start them in peat pots.

    Cucumbers even hate peat pots.

    My peppers and tomatoes flourish in the south-facing windows, but the tomatoes get very leggy no matter what I try, including moving the planting date two weeks closer to outside planting time. They usually get a couple weeks hardening time on the deck before going in the garden, which helps. As long as I am careful when planting the tomatoes outside, tying them up immediately while transplanting, they take off and the stems thicken up very quickly.

    Just about everything else we grow is sowed directly into the garden.

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