Soil

Soil
[photo: bed being prepared with organic matter in fall]
A recent phone call with my sister in law has made me think more about soil. She is having trouble with slow growth in her northern NJ vegetable garden and is puzzled. The area is sunny and was just built this year to increase her growing space. She had a load of top soil delivered for the area and planted in it. She did something similar at a school garden a mile or two away last season, and that garden is showing good plant growth this season. I told her I am not sure why the school garden is doing better, though she thought it might be greater earthworm activity and the longer time frame for the school garden to get some organic matter into it. In addition, I thought that underlying soil at the school garden might be better, that commercial top soils can differ, even if purchased at the same place, and, of course, the site is different. But I still think that the unimproved, commercial soil is the issue for uniformly slow growth.

People think that topsoil is the thing to buy and use, that it is rich and good soil for growing, there are a few problems with this: 1. Where is the soil from? It can be excavation dirt from building, which might mean it is not the top few inches of loamy soil, and the soil typology of the area can vary a lot. Did you know that some commercial top soils are dyed to look like rich, black earth and are really clay? 2. The top soils I have encountered (in bags, or bulk delivered) seem to have very little organic matter in them. When I have planted into mostly commercial top soils, my plants have not had great growth. Also I noticed that they seemed to clump and bake in the sun, which a soil filled with organic matter would not do. I know you need to start with something, that you can't make raised beds out of thin air, but you need to amend commercial top soils- they are insufficient in themselves for good vegetable plant growth.

I have an accidental experiment with this going on this year. In my main garden, I have a bed of tomatoes planted mostly in top soil. Yes, the soil was amended in the past, but not lately. These tomato plants are sort of scrawny and are not producing much. Most of my tomatoes, however, this year are in a separate garden area. This is an area that my husband dug last fall and we added some commercial top soil, as well as grass clippings, pine straw and leaves and buried compostable kitchen scraps and coffee grounds. I also worked in some organic fertilizer in the spring and lightly turned the soil a few times, watered it a few times, and covered it with a tarp to promote decomposition, weed suppression and dog digging suppression (though we discovered that my dog loves to rip tarps). The tomatoes in the new bed? I am jokingly calling it the “tomato hedge” or “tomato forest.” The plants are huge, full of fruit and I swear they are growing right before my eyes!

The advice I gave my sis-in-law (and to anyone building a new garden) was to side dress and scratch in some organic fertilizer this year. Starting in the fall, I suggested that she do what I did above and sheet compost (see composting entry) or work in the various amendments, watering and covering with an old tarp. I would bury kitchen scraps especially (to help them break down and not attract animals-she has a raccoon problem and neighborhood bears). I suggested that if her town or county has yard compost for residents, get some of that (though if you ever buy compost, beware of what the industry calls "biosolids"- that is composted sewage sludge, and can contain contaminants and heavy metals) and get some manure from local farms (dig it in- this should be done as early in the fall as you can, as the manure would need to break down enough before you could plant in it). Of course, if you have a compost heap or pit, make sure to add some of that “garden gold!”

If the soil is right, the garden should grow well. Happy Gardening!