advise for soil amendment

[kvet]

Long story short: obtained official soil analysis for family member to grow tomatoes. Findings included low nitrogen and very little organic matter (heavy clay). P, K, and micronutes were all excellent. Recommendations include adding some blood and feather meal, and digging in green waste compost to the soil at 4cu yd/1,000 sq ft. Area is roughly 200sq ft, so, we're looking at just under a cubic yard of compost.

Paralysis by analysis, I've made compost an issue. There's one place that provides it in bulk, however, we don't qualify for the minimum delivery. We can spend $40 more and they'll bag it up for us. My concern is potential herbicides in the material, since they accept clean greens throughout the county. Herbicides are bad for 'maters. A realistic concern?

Next option includes the soil amendments/conditioners from big-box stores (kellogg, G&B, etc). These are half the price, but it's not really a driving factor since overall we're looking at $75 vs $150. But they are bark fines and recycled forest product. Analyst dude says this is okay.

Final option is extra snooty Dr. Earth brand. OMRI certified, and mostly green waste compost with a few bits of unnecessary extras in it. Same price as bagged local compost company. Assume okay and no herbicides due to OMRI?

I'm leaning towards the Dr. Earth option, mostly because it does have the greenwaste compost. Below are links. Wish I could walk away from life and go have my own farm. With an ocean view and temperate weather year round. Next to a few good grocery stores, too, in case I get lazy.

Any opinions or better ideas?

Links to sample products:
Soil Amendment & Compost
Natural Garden Soil - Flowers & Vegetables | Kellogg Garden Organics™
Amend Garden Soil for Flowers & Vegetables | Kellogg Garden Organics™
Natural Choice(R) All Purpose Compost – Dr Earth

Many thanks

[estación seca]

I heard a talk by a soil scientist from our local University agricultural extension office. He said the idea of turning organic material into the soil is decades old and not correct. He said you are better off putting a thick layer of mulch on top, keeping it somewhat moist and letting the soil organisms do the work for you.

The organisms go through the mulch rapidly. My mulch disappears at the rate of about an inch/2.54cm a year.

He said the nature of the green waste mulch doesn't make any difference - sawdust, tree chips, anything without resins like pine bark - since soil organisms just eat plant material. You would want it free of pesticides and Round-Up, of course, because both can kill soil organisms.

I would pick the least expensive one you think is likely free of herbicides and pesticides. Lay down the mulch. Make holes down to the soil level and set your tomato root balls on that. Backfill with mulch. It's OK if only a few leaves are showing above the mulch. Tomatoes will root from the stems so you will get a better root system.

Another possibility is growing in containers while you mulch your beds. In this case I would also use a green manure crop and turn that under at the end of the season - alfalfa if it grows where you are, otherwise another annual clover. Inoculate the seeds first with nitrogen-fixing bacteria.

American Meadows is a seed and plant vendor. They have a lot of clovers for turning under while fields lie fallow.

[kvet]

Interesting. I wonder whether the no-till method can work if there's only one season left at this location, the family member may move by the end of the year. I don't think the clay will break up, but if we keep it moist I suppose the roots will grow through nonetheless.

[Ray]

I don’t think the top-cover is particularly applicable to a heavy, clay soil. The modifier is needed to open up the structure as much as to add organic matter.

We had clayey soil in PA and used peat moss, but with clay, the pH needs to be in the 5.5-7 range, as that can shift the clay crystals from face-to-face, to edge-to-face orientation, opening up the soil further.

[estación seca]

The soil scientist said microorganisms are much better at opening up clay than a gardener with a shovel.

[kvet]

Originally Posted by estación seca

The soil scientist said microorganisms are much better at opening up clay than a gardener with a shovel.

Wait'll these science types get a load of me (see attached).

The soil analyst suggested breaking up the clay 10-12 inches, and mix the compost in about 6 inches. Since this is likely the last season the family members will be at this location, I'll just go ahead and do it. We've got some beautiful weather ahead of us, and it's only 200sq ft so it'll be nice and fun.

[Leafmite]

There is the same problem where I live. Heavy clay. Lately, most people are doing raised beds. They buy some boards, use something to keep them together at the edges, fill them with good soil and plant whatever they want to grow. Easy success. You can make these beds as small or large as you want. If you move, the boards are removed and the soil is raked and spread over the rest of the yard.

Another thing people in this area do is to dig out the clay for a few feet, mix some of the clay with sand and organic material, add that in and then fill the rest of the pit with organic material. Sometimes that works and sometimes, if you get heavy rain and the water cannot drain from the pit, it doesn't (The neighbors have this set up and lost their tomatoes and peppers a few years ago because the water could not drain fast enough--usually it hasn't been a problem).

[fishmom]

Over the years, I have had good results with redwood compost products, as they seem to last longer and thus lighten the clay better. But like ES, my mulch disappears at a fairly rapid rate, and my clay is not too heavy. I would avoid adding sand to any adobe soil, as that may result in bricks if the organic component is not high enough.

[estación seca]

If it's for one season I would find a good farmer's market. How many jars of canned tomatoes do you want to move?

[Diane56Victor]

Originally Posted by kvet

Wait'll these science types get a load of me (see attached).

The soil analyst suggested breaking up the clay 10-12 inches, and mix the compost in about 6 inches. Since this is likely the last season the family members will be at this location, I'll just go ahead and do it. We've got some beautiful weather ahead of us, and it's only 200sq ft so it'll be nice and fun.

Love it!