It doesn't take a lot of space or money to create a successful seed starting nursery. This set up cost $20, and most of that was for things that can be used season after season.
Color me optimistic, but I’m calling “spring on its way.” If someone tells me it’s still winter, I’ll call them a stinkin’ liar. It’s spring and this means it’s time to start seeds in preparation for the growing season. It comes quicker than you think!
But along with being optimistic, I am also not rich enough to buy those pre-packaged seed starting kits I’ve seen in the store. I’d rather spend my money on other things like a really nice microbrew once in awhile. I also have a small house (about 800 sf total) and not much room to construct the seed-starting nursery to rival the Colosseum that I’ve seen other people manage. So my seed starting set up has to be cheap, productive, and take up little space.
Luckily, I met all of my criteria for a total cost of about $20 (not counting the cost of seeds). And over half of that cost was for a clamp lamp and a grow bulb, which I can use again. That $20 went towards constructing a heat bed, which is a way to supply warmth to the roots of developing seeds and enhance germination, and the starter medium in which I planted my seeds. The rest of the material was either recycled or used. Here’s how I did it:
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HEAT BED HOW-TO
What you need:
- A sturdy container for the project (I repurposed an unused plastic bin)
- Non-clumping kitty litter or sand
- Indoor-outdoor rope or string lights
- Egg cartons (or your seed-starting container of choice)
- Seed starting medium (potting soil will work)
- Clear cover (plastic or glass) for the container
These lights, covered with a layer of kitty litter or sand, provide gentle heat for germinating seeds.
I already had an unused, under-the-bed plastic storage bin, measuring about 17″ by 36″, which was going to serve my purposes well. The plastic bin served as the base for my heat bed.
I took the bin and placed it on a bench in my closed-in porch. Then I poured half of a large bag of kitty litter into the bin and smoothed out the surface. Next, I laid one string of lights (with a 33′ string length and 100 bulbs) on top of the kitty litter, making sure the lights were mostly evenly spaced in the bin. Lastly, I covered the lights with the rest of the kitty litter and plugged the lights in to allow them to start heating the litter (again, you can also use sand…whichever is cheaper in your area).
You can use a wide variety of containers for your heat bed, including used flats from nursery centers, sturdy cardboard boxes, or even wooden boxes. The box just needs to be deep enough to hold a layer of kitty litter/sand and lights, and sturdy enough to withstand watering your seedlings for several weeks. Aim for about a 2- to 3-inch layer of litter or sand, with the lights layered in about half way. That will hold the soil temperature at about 92F, if your ambient air temperature is in the upper 60s or low 70s. For most seeds, a 92F soil temperature is about right to enhance germination. Just make sure that the lights you use (be they rope or bulb-style) are for outdoor use; you’ll be watering your plants and your lights need to withstand that.
With my heat bed warming, it was time to plant some seeds! I had saved egg cartons for several months and used them as my seed-starting pots, separating the lid with a knife. The lids are great for starting seeds that need to be thinned after germination, like lettuce, and the carton portion is great for your other seeds. When the plants in the cartons are large enough to be planted into larger containers or transplanted outdoors, I take scissors and cut the whole egg carton apart into its individual pots and just plant the thing, carton and all (it will degrade in the soil).
Yes, you can use Styrofoam egg cartons for this, and they will retain moisture better for germinating seedlings. However, if you cover your heat bed (as you should) with a layer of clear plastic or glass to retain the all-important humidity for your seeds, this won’t be as much of a problem. Also, you can’t plant the Styrofoam directly into the garden, which means disturbing the roots of your young plants when you remove them. Lastly, there is some serious question about the Styrofoam starting to degrade and leaching the chemicals into the seedling soil, which will ultimately make its way into your garden. To me, the benefits of Styrofoam cartons (better moisture retention) are alleviated by covering the heat bed, which you have to do anyway.
Lastly, your heat bed will need a supplemental light source, unless you’re lucky enough to have a true greenhouse. Seedlings started indoors without proper lighting will just end up spindly and less healthy; it’s worth the cost to buy a supplemental light set-up to give your seedlings the best start possible. And such lighting doesn’t need to be expensive. I bought a clamp lamp and a high quality grow bulb for about $14, and I can use this season after season (depending upon how long the bulb lasts, of course).
PLANTING SEEDS
I used an organic seed starter mix for my seeds, filling each egg cup to full. It’s a good idea to invest in a seed starter mix, which is formulated for the special needs of germinating seeds but I’ve known people who use regular potting soil and that works, too. I only needed 1/2 a bag of mix for six dozen egg cartons, and it cost $3.50 a bag for organic. I have plenty of mix left for other seeds I’ll start in a few weeks or so.
A basic rule of thumb is to plant seeds (like this tomato) three times as deep as the seed's thickness. But beware, this isn't always the case.
After you have your mix ready, just follow the directions on the seed packets about how deep to sow each plant, but a general rule of thumb is to plant a seed three times as deep as the thickness of the seed. However, this isn’t always true; for instance, salvia seeds need light to germinate and therefore shouldn’t be buried in the soil at all. So if you’re a seed saver (and you should be) or just don’t have the original seed instructions handy, it’s always a good idea to have in your gardening notes the correct seed planting method for all the seeds in your arsenal. You can also look this information up online.
After my seeds were planted, I simply moved the cartons to the heat bed, watered them all well, and covered them with two pieces of acrylic a neighbor had left over from a project of his own. I’ve tried saran wrap for this in the past and it just doesn’t work. I’ve also saved the clear plastic flat covers you can sometimes get from nursery centers and these work well, too (as was their intended purpose).
This is all fine and dandy, but can all seeds be planted indoors to get a head start on planting? And when, exactly, are you supposed to start the seeds indoors? These are indeed things the wise seed starter looks into before introducing their precious seeds to soil.
INDOOR SOW OR NO?
First, I recommend going through your seeds and determine which ones really need to be direct-sown into your garden after the danger of frost has passed, versus starting seed indoors and transplanting outside. Plants recommended for direct-sow usually do not transplant well, and there can be high mortality rate if you try that route. And the older these plants are, the worse the transplant shock — and subsequent plant death — can be.
But there is some disagreement about which plants are best left for a direct-sow approach, (It couldn’t be easy, right?). For instance, some sources recommend direct seeding melons, but since I live in a chillier clime I’m planting them indoors to get a head start. After the seedlings germinate I’ll transplant them into large biodegradable pots that I can simply place into the soil with minimal root disturbance. There’s nothing wrong with experimenting on your own; horticulture is part art and some people just have a knack for doing what others say isn’t possible.
Plants that are recommended for direct-sow include lettuce, spinach, radishes, cucumbers, most squashes, peas, beans, corn, and carrots. Some flowers prefer direct-sow, too, including sunflowers, nasturtium, zinnia, bachelors button, plus a few others. But again, I’m going to start the zinnias and sunflowers indoors and transplant them. If garden centers can do it, so can I, right??!!
Covering your seeds with plastic or glass allows for moisture to be retained, which is necessary for germination and good plant health.
The timing of all this depends upon where you live and what your “last frost date” is. There are different recommendations about when you should sow plants indoors, and they are all roughly related to this date. You can visit the website of your local Cooperative Extension Service for this date. Then, you’re supposed to look at the seed packet and, if you’re lucky, it will say something like, “Sow indoors two weeks before the last frost date.”
But because I am lazy, I just go to this handy dandy resource kindly supplied by the Farmers Almanac (find it here). Just type your zip code into the Location field provided and it will spit you out a nice table that includes lists of vegetables and the recommended date to either start seed indoors or direct sow outdoors in your area. It even includes a “moon favorable date,” if you prefer to use the moon as a guide for planting. It’s a great resource and takes the hassle out of figuring out when you need to time your seed planting.
Deb Meyer
February 18, 2012 at 3:54 pm
Wow! I have been thinking the last couple of days about starting some seedlings indoor for my small vegetable garden. The holdup was where to get all the information about how to set up and voila here it is. Thanks so much! Can’t wait to get started!
Rural Spin
February 18, 2012 at 4:01 pm
That’s great! Have fun doing so!
Mark
February 18, 2012 at 5:03 pm
Very cool idea to use a string of lights under a layer of kitty litter as a heat bed for starts! Kitty litter is a very neat growing medium, it can be used for the root medium in a hydroponic set up, many kitty liters use Diatamacious Earth in the kitty litter which kills bugs, All of the bugs! Good bugs and bad bugs unfortunately.
H. W.
February 18, 2012 at 6:37 pm
Pro gardeners start seeds in flats – which are basically boxes without any dividers at all. When the seedling has at least two ‘true’ leaves (not the cotylons) they ‘prick’ out the seedling and plant it in it’s final home. So, you could be starting your plants in the bottom of a cardboard box or even straight into that plastic box just filled 2 or 3 inches with good dirt and don’t water it too much. Use a spoon to scoop out the seedling to plant it in your garden. It’s not like the seedling is gonna care what you use! (It took me years to get over wanting to use little cells and even 3.5″ boxes!)
Rural Spin
February 18, 2012 at 6:48 pm
Indeed, H.W.! I used to be a professional gardener and have worked in professional greenhouses and botanic gardens–you’re right that the method you describe is great for professional operations because of the many, many plants that can be grown this way. I still prefer individual cells for many plants because of transplant shock issues, and also I lack a lot of space and time needed for the method you describe. But as I say in the article, gardening is part art and in the end everyone has their own personal likes, dislikes, and successes! Thanks so much for sharing your tips!
Ken Holsinger, Key WEst FL
February 19, 2012 at 12:19 am
Have used the egg cartons to start tomatoes but planted in 1/2 egg shell then set in the box. When moved outside planted the shell in ground after giving it a few taps to start fracture lines for roots to get out.
Rural Spin
February 19, 2012 at 1:14 am
Yes, that is definitely a great idea. I’ve been tempted to try this myself, but always end up tossing the egg shells in my compost before I remember to save them for seed starting.
Using the shell, though, must definitely help with moisture retention!
Allison
February 19, 2012 at 12:32 am
Great article! I have a question about the rope or string lights. Nowadays most are marketed as LED lights, which are much cooler than traditional incandescent. Would those be warm enough, or should I search for the good old-fashioned kind?
Rural Spin
February 19, 2012 at 1:12 am
Great question, Allison! I haven’t used the LED strings myself for that very reason (and because I just outdoor light strings that I already have). But I just don’t see the LED strings generating the heat needed for this purpose. (I do have LED light bulbs in my home and they are significantly cooler than my other bulbs!)
bewitchingdragon
February 19, 2012 at 8:30 pm
Reblogged this on bewitchingdragon.
Teri
February 20, 2012 at 12:08 am
I suspect non-clumping kitty litter is what you use. ??
Rural Spin
February 20, 2012 at 1:07 am
Yep…the article specifies non-clumping in the materials list.
Drew
March 4, 2012 at 9:08 pm
Great article, i have been saving 1/2 egg shells and cartons to start my seeds but was worried about how cold my closed-in-porch gets. the string lights are a genius idea, i’m going to give it a shot. thanks!
beyond diapers
March 12, 2012 at 4:05 am
Thank you! All the other DIY seed starter set ups looked like a PITA. This looks 100% do-able!!
Rural Spin
March 13, 2012 at 3:03 pm
Ha! What is a PITA?!
beyond diapers
March 16, 2012 at 6:08 pm
Pain In The Ass
Jillyn
March 16, 2012 at 5:38 pm
Thank you for this post. I just set mine up today. My lights aren’t completely burried (i don’t know if i did somethign wrong) but i hope it still works. I’m worried about something getting too hot and starting a fire though :-/
and PITA means Pain In The @$$.
Thanks for the tutorial!
Rural Spin
March 16, 2012 at 11:07 pm
I’d need to see a photo to determine if the lights are buried enough (sometimes mine aren’t completely buried, either), but I’d be surprised if the temperature got so high to cause a fire. But if you’re truly concerned, it might be good to use a thermometer and monitor the temperature for a bit.
Dawn
November 26, 2012 at 10:40 am
Do you leave the grow light on constantly?
Rural Spin
November 29, 2012 at 9:14 am
No…just during the day. I like to mimic nature as much as possible, so I have a timer on the light where it goes on at sunrise and off at sunset. Plants need their rest, too!
Tama Nash
December 3, 2012 at 5:17 pm
This whole thing is toooo awesome thanks to everyone of you
Joel
December 27, 2012 at 8:19 pm
I may have missed it in your blog post but what are you using as the clear plastic/glass cover and how deep is the container you are putting them in?
We live in the PNW and will need to start all our ‘warm weather plants’ this way… melons, peppers, tomatoes, cucumbers… I’m thinking that they’ll need more space to grow before I plant them outside?
Thanks
Rural Spin
December 28, 2012 at 8:00 am
I’m using just acrylic sheets from Home Depot that come pre-cut. They have different thicknesses but I got the thinner ones. These work great because you get two, and you can open the middle to provide ventilation and monitor the heat level. For the tub, it’s an under-bed storage tub that you can buy–they are a standard height. I think about 5″ or so. It holds one large bag of litter (can’t remember the exact quantity…). After the seedlings are well on their way, you’ll need to transplant them to larger pots with an actual growing-on soil (I use a seed-starter mix to start seeds, but you don’t have to). At that point they don’t need the seed nursery and can be moved to southern-facing shelves (or an area with a grow light or two so they get bright light for healthy growth). I transplant/move mine from the seed starter nursery and onto shelves when they get two sets of true leaves. Or, as all of your seedlings pop and grow, you can just transplant them into pots and set them on the kitty litter in the tub but make sure you unplug the lights–after germination the plants don’t need it anymore. (Or sow the seedlings directly into your garden for cool-weather plants if your soil is warm enough).
Marlin
December 29, 2012 at 8:19 am
New at starting seedlings, I thought you needed to keep a light directly close to the seedings?
Rural Spin
December 29, 2012 at 3:40 pm
It depends upon the light, Marlin, and how hot the bulb will get…you don’t want to fry your seedlings if the bulb will get too hot for them. It also depends upon how many foot candles a specific bulb will put off…the more intense the light, the farther away it can be. For this kind of light (a basic, cheap grow-bulb from a hardware store), this distance is good.
Kim
February 12, 2013 at 4:31 pm
Awesome idea! Can’t wait to try! I have nearly everything on hand too- except kitty liter. Having a cat, I prefer using the clumping kind- easier clean up. Obviously, I see why that is not recommended
. I do have a silly question though- would LED lights warm the liter the same way?? The only outdoor ones we have are LED.
Rural Spin
February 13, 2013 at 7:16 am
No, LED lights do not get warm enough.
Nadine
March 5, 2013 at 10:34 am
I live in Canada, west coast, very close to the border. Can I set the tray up in an unheated greenhouse and therefore eliminate the grow light?
Rural Spin
March 6, 2013 at 10:46 am
The grow light could be eliminated in a greenhouse. You’ll need to watch the temps of the soil, though. I’ve learned the hard way that if the soil gets too hot, seeds won’t germinate, either. I just mention this because I’m not sure what the temperature fluctuations are like in your greenhouse during the day. Or at night. Soil temps ideally would be between 65F and 85F degrees consistently, depending upon the seed being germinated.