Soil Amendment?

Asked March 19, 2013, 11:26 AM EDT

Hi- I am preparing a 30' x 100' garden bed on essentially clay pastureland (Hazelaire, Rittner) that will have 30' rows of blueberries, raspberries, strawberries, Pinot Noir and Marechal Foch grapes. The pinots are going on a slope. In addition, about half of it will be a regular vegetable garden. We are located south of Lebanon off Ty Valley Road. Last weekend I did soil testing with a home test kit. The PH is 6.8. The nitrogen was very low (as in the water in the test tube remained clear), the phosphorus was very low to non-existent, and the potash is high. Our water has a lot of iron in it. We are at about 400'elevation. I had the area plowed last fall but the fellow was only able to get down about 5" because the ground was so dry and hard. Right now you can dig deeper. Drainage is very poor. I know it needs compost. Will a plow do the trick or does it need disked? How much compost would I need to order? Is there a kind of locally available compost that would be better? What other soil amendments should I add? Should I put bark dust in with the soil for the blueberries? I'd like to get the garden started right, and since I am planting shrubs and perennials, I'd like to get the amendments done soon so that I can get them out of their containers and into the ground. So also, how soon can I get the area disked or plowed? Thanks, Mary

Linn County Oregon

1 Response

Is there any slope? If there is a gentle slope, I recommend that you plow and terrace. Have a contractor plow the ground when it is just the right moisture, not too wet and not too dry. Your contractor can help you make the timing decision based on their experience. If the soil is too wet, it will form a slick ribbon and not break up. Time to plow will occur this spring and the perfect time to plow may only last a week or so.

Once the ground is plowed, move the soil down hill in such a way that there is a below below and a walking path above. By establishing an informal terrace, you will improve the drainage in the bed.

The most economical way to amend your soil is with composted manure. I recommend that you interview some ranchers or dairy people and see if they have come composted manure that they will deliver in a truck load. A garden that is 30 by 100 ft is about, approximately one tenth of an acre. If you can afford it, apply four tons of composted manure per acres or about 600 pounds of composted manure (manure that is not too wet, but instead, is fairly dry). If you can afford it, apply by volume up to six yards of fairly dry manure.

Beyond that, add phosphate rock and kelp meal to your compost pile, and mulch with your finished compost when ever possible. Don't mix bark dust with your soil. It will tie up nitrogen. Instead, mulch the paths with the bark dust and let the worms slowly incorporate it into the soil over a period of years.

In my experience the best soil building program does not depend on salt based fertilizers (example: triple sixteen 16-16-16). Nor does the best program depend on manure and compost only. The best program uses manure, compost, and a little salt based fertilizer. A little bit of salt is not a bad thing in a good soup. Just not too much.