Growing Transplants Without Fossil Fuel Heat

Two years ago I helped my then-5-year-old son plant a sunflower seed in March. I told him was much too early. Undaunted, he tucked the seed into a small pot filled with soil. I was sure his attention would not span the months it takes for a seed to grow into a large, healthy plant, and sure that a poor sunflower planted in the dark and cold of March would languish on our windowsill. But as our children and nature often do in marvelous ways, both my son and that sunflower proved me wrong. Phoenix regularly tended his little plant. It survived his overwatering, and the wan March and April sun, to be planted in our garden. That sunflower grew taller than Phoenix by July, and made prolific huge blossoms.

And so an idea was born. Phoenix had been seeking a way to earn money on the farm, so I proposed that since he liked sowing seeds so much, we could grow veggie starts to sell at the annual Spring plant sale at Ithaca High School in mid-May. The truth is that he only helps with a very small portion of the work, but each year I hope his contribution will grow with both his abilities and his desire to make money, and that this will become more his project than mine. We’ll know how this idea worked out in a few more years!

Starting seeds in March and early April requires both heat and light in abundance. Our home is warm, but lacking in sufficient space for all the plants we want to start. And the fake sun that emanates from indoor “grow lights” tends to produce leggy, fragile starts. Natural light is best for healthy starts, but adding gas or electric heat to an outdoor growing space is expensive enough to tip the economics of very small-scale transplant production into the red. Lucky for us, there are other FREE sources of heat!

Look at all that steam! Make sure the compost you get is as fresh as possible, so you can capture the heat.

Fresh, uncomposted manure generates sustained heat for a period of weeks. And of course, once it has cooled, it has the benefit of being a fantastic fertilizer for gardens. Harnessing this compost heat is not a new idea – it has likely been done for thousands of years by resourceful humans. But it wasn’t until we saw a video of how our local Muddy Fingers Farm implements the practice that we realized how well it would work for us.


In late March we use small square bales of mulch-quality hay to create two long rectangles inside a 12’ x 24’ plastic-covered hoop structure (a “hoophouse” or “high tunnel”). These rows of bales will serve as the walls for the manure beds. We use baling twine to tie the rows of bales to each other, so they don’t get pushed outward as the manure is loaded into the inside of the rectangles. Then we get two truckloads of horse manure mixed with sawdust from our friend’s stables up the road. We dump it into the rectangles, filling them up to the top side of the bales. We allow it to off-gas for 24-48 hrs, and then start loading trays seeded with bottom-heat-loving seeds like peppers and tomatoes.

The plastic covering on the hoophouse provides one layer of protection against frost, and the heat from the manure helps too. But on really cold nights, we add another set of hoops just above the plants and drape frost blanket or Remay over them to help keep the heat in.

Phoenix and I chose to grow only purple varieties of plants, both to differentiate ourselves at the plant sale and because I love purple vegetables and flowers so much. He has helped with seeding and writing tags for each pot, but so far I haven’t been able to get him to help build the manure beds. I think I might be stuck with that chore for a while, until he builds more muscle, height,  and shoveling skills. Lucky for me, it’s work I like, and tending all those baby plants helps me survive the last of the dreary cold weather as the growing season is just beginning.

Come visit us and all our purple transplants at the Ithaca High School on Sat May 18, 2019 from 9a-2pm. Shelterbelt Farm will be under a purple pop-up tent of course!

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