However, despite the vacations, Kelley still managed to amend her good ol' Contra Costa clay just in time for planting by June 1. It was sort of an homage to that classic "Faster, Kelley! Dig! Dig!". Arti "interviewed" her and she has this advice to share:
Arti's Question: You have a backyard that had grass and other stuff growing on it at one time -- why did you amend the soil before planting?
Kelley's Answer: There are 2 main reasons I had to amend my soil.
First, the grass that was once there is long gone, especially since we ran over it repeatedly with heavy equipment when we remodeled the house. That said, the type of suburban grass that was most likely there has shallow roots. Therefore, it never needed to reach deep into the native clay. The tomatoes and other plants I've put in have deeper roots.
The clay is basically impenetrable -- heavy, gluey glop in winter, and brick-hard in summer. Remember what all those Spanish missions were made of? So, my soil had to be loosened up and material added to keep it from returning to its original dense, airless state. This picture sums it up: look at the flat, packed and cracked character of the unamended part of my yard.
Second, a simple soil-testing kits from the hardware store revealed that the soil was an empty plate. Now, there may have been some nutrients in it, but they were "locked up". This means that nutrients may be present, but the plant does not have the chemical or mechanical processes to use it. For example, this winter we had a good amount of rain, which contains lots of nitrogen that plants love.
However, that nitrogen is in an organic form that plants cannot use. Bacteria found in soils convert organic forms of nitrogen to inorganic forms that the plant can use. Nitrogen is taken up by plant roots and combined into organic substances in the plant, such as enzymes, proteins and chlorophyll. Thus, regardless of whether there might have been any nutrients in the soil, it was essentially an empty plate for the plants.
To fix this problem, I double dug several planting beds and added the following for every square yard of clay that was dug up:
- 70% Compost, for general enrichment, aeration
- 10% Bone meal, as a phosphorus boost for fruit production
- 10% Kelp meal, for potassium and trace minerals
- 10% Worm castings, for enrichment
Q: After amending the soil, did you just plop the plants in?
A: Tomatoes being the heavy feeders they are, I added more goodies to the holes in each new fluffy bed (see right) to increase the possibilities for a succesful crop. To each 12" deep hole I added:
- 1 fishead for a calcium boost, which guards against blossom end rot. I got mine at Ranch 99 for $.79/lb, but any Asian-style market is likely to have them;
- 3-4 crushed eggshells, also for calcium, that I saved over the winter;
- 1 handful of bone meal (from Navlet's) which is rich in phosphorus and critical to fruit production;
- 1 modest handful of worm castings, also from Navlet's, for a delicious first feed;
- the recommended dose of mycorrhizae from Bountiful Gardens, where you can read about the amazing things this product does.
Then, after the plant was lowered into the hole and the soil carefully, gently backfilled, I topped it off with nice drink of Dr. Earth's 5-7-4 plant food.
Q: Any other interesting things you found out in the process?
A: Yes, WAY!
Remember how we always say to rotate tomato crops? Well, when I dug up last year's bed, I found several fat, gross hornworm pupae, just waiting to emerge into their adult stage as a hawk/hummingbird moth. Sure am glad I did not use that bed again!
I also discovered that my yard is not all the same clay, nor even all clay. I found brown, red, green, and black clay...not sure what it means, but food for thought. Then, in a thin band around the inside of my fence, I found nice soil with perlite in it and all. This was obviously the remnant of what were perimeter plantings when this was a traditional suburban lawn.
Finally, I noticed that one of our tomato varieties, the White, likes to pretend it has leaf curl -- see this picture at right. So, if you are one of our customers who bought this variety, do not panic.