Preparing Soil for Greens
When it's early in the season and nearly time to plant a host of greens, put in a little time with your garden soil to prevent weed problems.
Working the Soil
Work the soil once or twice in the week or so before planting time. This puts the soil in good tilth, with no clods or soil chunks, and kills early-growing weeds. Weed seeds are quite small and must be near the surface where there's moisture and warmth before they can sprout to life. When they do sprout, you have to look hard to see them. Working the soil, even raking it, will get rid of the tiny weed seedlings before they shoot up.
By periodically going over the soil before planting, you destroy most of the weeds that could be a problem later on. Work the soil one last time a few minutes before planting. This eliminates most weed seeds that have germinated since your last outing and will give your greens an even chance against the few remaining ones.
Greens Love Rich Soil
The healthiest and best-tasting greens are those that grow quickly. The important contributors to rapid growth are a steady moisture supply and fertile soil rich with decomposed organic matter or humus. Make it a point to regularly work plenty of organic matter into the top six to eight inches of soil. Use leaves, compost, grass clippings, garden residues or easy-to-grow cover crops, such as buckwheat, cowpeas or annual ryegrass.
Organic matter in the soil helps it to act like a sponge, retaining moisture. Without organic matter, the soil may drain too quickly, and shallow-rooted crops, like lettuce, will dry out and stop growing. When growth is interrupted like that, food quality goes way down.
When you spade or till all this organic matter into the soil, you're feeding the teeming soil life - those millions of microorganisms that break down the organic matter into nutrient-rich humus. Feed them, and they'll feed you in return.
The microorganisms in the soil and the plants' roots have to breathe, too, and organic matter gives the soil a porous quality so that oxygen can reach the roots. If you have heavy soil that doesn't drain well and crusts over after a rain, the particles of organic matter will wedge themselves between the tightly packed soil particles, so that air and water can circulate better.
Lettuce, spinach, chard, beet and turnip greens, and most of the other greens, prefer slightly acid soil with a pH of 6.0 to 6.5. The term pH refers to the measure of soil acidity or alkalinity. The pH scale of measurement runs from 1 (very acid) to 14 (very alkaline), with 7 as neutral. (In nature you generally find the range between 4.0 to 8.3.) If your soil pH is too high or too low, your crops may disappoint you. Spinach, for example, will be stunted and less tender when the soil pH is down below 6.0.
To test your soil pH, you can buy an inexpensive testing kit at a garden center or send a soil sample to a commercial lab or to your local Cooperative Extension Service, if they do soil tests. The results may indicate you need to add ground limestone to raise your pH, or you may have to mix sulfur into the soil to lower your pH.
The soil test report will indicate what and how much to add to your soil to bring it into the correct range.