Seedling Soil Mix, Seedlings

Several people have asked me over the years what soil media I use to start my seedlings. I loosely follow Eliot Coleman’s method listed in his book New Organic Grower. If you are not familiar with Coleman this link on Coleman  gives a  brief description. He is the father of cold season or four season gardening and one of my gardening heros. Below is the soil mix:

Soil Mix

  • 4 parts (qt) coco coir
  • 4 parts (qt) peat moss
  • 2 T colloidal phosphate granules, finely ground with a mortar and pestle
  • 2T greensand
  • 1 part (qt) worm compost

The day before or a few hours soak the coco coir with an equal amount of water. While that’s soaking, coarsely grind the phosphate granules into a fine powder. An inexpensive mortar and pestle set works well. Phosphate fosters strong root development and the smaller the surface area the better absorption by the tiny seedling roots.  After the coco coir has absorbed the liquid,  mix the peat moss, amendments and 1 part worm compost. I generally store my soil media in a covered five gallon plastic bucket. It lasts for months.

Sweet Peppers

One tip I’ve found over the years for seedlings is leave the nitrogen out of the mix, especially for peppers. Technically nitrogen is in the soil mix from the worm compost but don’t add any additional nitrogen amendments such as blood meal or alfalfa meal at this stage.

Photo is last year of potatoes in a bag after final addition of soil media.

Another tip is for potatoes.  I use only half compost and half peat moss without any additional amendments when I plant them in bags. Otherwise I have more leaf growth and less potato development. Since I am in hardiness zone 6a/6b, I won’t put any out until end of April or beginning of May depending on weather temperatures. Varieties I’m using this year are Katahdid  a white potato, and  new for me this year are Red Maria a red potato and  Covington a sweet potato.

Tomato Seedlings

Tomato seedlings are popping up too, and I planted cherry tomatoes the other day. The regular sized (6 to 10 ounces) varieties I am growing this year are Box Car Willie ( love this name) , Abe Lincoln, Better Boy and Jasper is the cherry tomato, all indeterminate tomatoes. That is they produce all season until frost. An experiment this year in the greenhouse will use Geronimo and Estiva tomatoes, something I’ve never done. Geronimo is a variety used in trials in hoop houses or greenhouses. Estiva is another.

I still have other seeds to sow but that’s for another day. Until next time.

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