Long-term Soil Improvement in Bad, Sandy Grit

Yesterday a friend tilled under most of the rye cover crop we planted.

The featured image in this post is from a few weeks ago – and here is what that area looks like now:

That area to the left was all green rye, a couple rows of turnips, and some clover and daikons yesterday morning. Now it’s going to be part of my NOGRASS Garden experiment.

As previously reported, this soil is awful. In order to improve it beyond a single season, we are making biochar to till under.

That is a biochar burner that belongs to some friends who dropped it off for us to use. Thus far we’ve made two loads of char, for a total of perhaps 80 gallons. This biochar burner design is not particularly efficient but it is easy.

My soil improvement plan for spring involves adding composted manure, charcoal, bentonite, azomite and Steve Solomon’s fertilizer mix to the soil. This should change the grit structurally as well as loading it with trace minerals.

The soil’s exchange capacity is abysmal and the char and bentonite will help that, with the latter helping humus to stick around much longer than it would in non-clayey soil.

If I had worm castings, I would add those to increase microbial and fungal life. I have seen zero worms here. I’ve got a bathtub I will eventually make into a worm bin but I have not done it yet. Purchasing castings is simply too expensive. However, once I get some life and some chop-and-drop going in my beds, the worms should move in.

The fertilizer mix Stave gave me is:

4 quarts cottonseed meal
1 quart kelp meal
1 quart garden lime (better to use 2/3 quart garden lime and 1/3 quart dolomite)
3.5 cups bonemeal
2 cups pelletized gypsum
2/3 cup potassium sulfate
2 tbsp manganese sulfate
2 tbsp zinc sulfate
1.5 tbsp borax
2 tsp copper sulfate
1/8 tsp sodium molybdate

This recipe treats 100ft2.

However, dogs have been tearing up my beds when I use bonemeal, so I am going to switch my phosphorus source to MAP (Mono-Ammonium Phosphate) instead. When I asked Steve about it, he said it would work but that I should lower my cottonseed meal by 1/4 to account for the extra nitrogen in MAP.

As Steve writes:

“Soft Rock Phosphate or Guano are acceptable in Organics. Use about the same quantity as when you use bonemeal. There is also MAP, which is a commonly used fertilizer. MAP also provides some N; if you use it you can reduce the amount of seedmeal by 1/4. MAP is 23% P. Use 400 gm/100 sq. ft. This also provides about 1/3 the amount of N you need so you can reduce the amount of cottonseedmeal by 1/4. Trouble with chemical N is that it leaches, especially from soil like yours that has so little cation exchange capacity. MAP’s N is in ammonium form, which is a cation, but still, your soil won’t hold it well. If you use MAP, perhaps best if you include only half the dose initially, like 200 gm/100 sq. ft. And then side-dress the same amount about six weeks later.”

Today I am headed out to buy some more amendments, then I will start making the beds. My current thought is to make the beds 5′ wide, with 3′ wide pathways. This allows a row of perennials down the middle of each bed, with space around those for planting vegetables.

Stay tuned.

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