To get a jump on gardening we need to be ready, but the weather doesn’t always cooperate. We start seedlings with the anticipation that the weather will comply, and be dry and warm enough for our tender babies. But that usually isn’t the case in early spring.
A great low-tech way to start seeds and keep the seedlings warm during the first tender growth is to use a hot bed. Common in Europe for market gardens, the idea was readlily adapted to big city market gardens in the US as well, since there was never a shortage of hot horse manure from livery stables in every city. After the Civil War, Peter Henderson was a very successful market gardener, stretching his growing season using the hot bed method for growing lettuce in the off season, and forcing other popular vegetables for sale in the big city.
On any farmstead there is always manure to be had, and this is one way to squeak one more use out of this precious commodity before it heads to the compost pile.
We have two small 20′ x 20′ greenhouses that we built for brooding chicks when we sold eggs. To make these user friendly, we planned a personnel area for the humans. It is a great place to store feed and extra bedding and also a warm, toasty area for starting plants and keeping them warm until the weather breaks.
Hubby built a 2′ x 3′ bottomless box out scraps for my small hotbed. I fill this with manure and bedding about two weeks before I want to start seeds. I want the compost to reach its peak temperature, and then when it starts to decline and reaches 80°F, I can place my flats of seeds on top of the compost. That temperature is a good range for most seeds, if you’re starting tomatoes and peppers, 85°F would be better. I keep the hot bed loosely covered with a piece of plastic, to keep the humidity up. Once the seedlings emerge, the cover comes off during the day, unless it is very cold. At night the cover goes back on in case of a frost.
I am hardening these brassica and salad green seedlings off now, so 60°F is a great temperature. I am not covering this at night. These plants are almost ready to plant out.
I also use electric heat mats to start seedlings, but this method is free, using no electricity. I have two boxes, and to have a succession going, I need to have another box heating up and ready while this one is cooling down. When the compost gets too cool to start seeds, you can lift off the box, remove the pile and refill with fresh manure and bedding.
If the box does not heat up, you need more manure, or if you are confident you have quite a bit of fresh manure, add water. Monitor the temperature, if it doesn’t rise in a few days after adding water, you do need more manure.
With a few scraps and a wheelbarrow of manure, you can have an effective non-electric way to start seeds and wait out Old Man Winter!