Soil Health and Composting

Test before you feed

Most garden problems blamed on fertilizer are really soil problems: the wrong pH, too little organic matter, or more phosphorus already present than the plants can use. A soil test tells you what’s there before you add anything.

Taking a sample is simple ¹:

1. Scrape away any mulch, compost, or sod.
2. Dig the top 5 to 7 inches in four random spots across one area (ten if you use a soil probe), about a cup in total.
3. Mix them in a clean container. Keep the vegetable garden, the lawn, and the berry patch as separate samples.
4. Send it to the UW Soil and Forage Lab through your county Extension office.

The standard test reports pH, organic matter, phosphorus, and potassium, with recommendations for lime and fertilizer; options include soil texture and a lead screen ¹. Run the lead screen for a garden near an old house or barn, where decades of lead paint chips may have fallen along the foundation.

Organic matter is the lever

Good garden soil is well drained and rich in organic matter ². Organic matter holds water in sandy soil, opens up heavy clay, feeds soil life, and releases nutrients slowly. UW Extension’s guidance is to work in 4 to 6 inches of compost on an in-ground garden, and to fill raised beds with topsoil and compost mixed 1:1 ². Most homesteads have the raw material for that compost already: leaves, grass, garden waste, kitchen scraps, and bedding from the chicken coop.

Build the pile

A hot pile turns yard and kitchen waste into compost in about 6 to 12 weeks ³. The recipe:

• Ingredients: about two to three parts browns (dry leaves, straw, hay, small sticks, newspaper) to one part greens (fresh grass clippings, trimmings, fruit and vegetable scraps) by volume ³. Browns supply carbon, greens supply nitrogen; this ratio keeps the microbes working fast without stinking.
• Size: at least a cubic yard, 3 to 4 feet high. Smaller piles can’t hold heat; piles over 5 feet compact and go airless in the middle ³.
• Build: start on a base of twigs or straw for air, chop anything thicker than about half an inch, and stack alternating 4- to 6-inch layers of browns and greens ³. Bury food scraps 8 to 12 inches inside so they don’t draw animals or smell ³.
• Water: as damp as a wrung-out sponge; a squeezed handful should give a drop or two ³. A shovel of finished compost or soil adds the microbes to get it started.

Heat and turning

Within a few days the center heats up. Watch it with a long compost thermometer ³:

• When it heats and then starts to cool, usually after about a week, turn it: fork the edges and top into the middle and add water if it’s dry.
• If the center passes 150 °F, turn it sooner.
• Don’t turn more than about once a week. Each turning brings in air and the pile reheats, a little less each time ³.

As it works, the pile shrinks to about a third of its starting height ³.

Finished and cured

Compost is done when it’s dark, crumbly, and smells sweet and earthy, the original materials are unrecognizable, and the pile stays within about 10 °F of the air temperature ³. Sift out the chunks and put them back in the next pile.

Then let it cure for at least three weeks, longer if it’s going into seed-starting mix or around transplants. Unfinished compost can harm young plants and temporarily ties up soil nitrogen as it keeps decomposing ³.

What to take from this

Test first: the top 5–7 inches from four spots per area, mixed, sent to the UW Soil and Forage Lab, with a lead screen near old buildings. Build organic matter with compost (4–6 inches worked in, or 1:1 with topsoil in raised beds). A hot pile is about a cubic yard of two or three parts browns to one part greens, layered, damp as a wrung-out sponge, turned when it cools after heating, done in 6–12 weeks, and cured at least three weeks.