Southern California Coastal & Inland Valleys
Plant Trees Properly for Good Root Growth
Tree roots can extend almost four times the distance from the trunk to the dripline. The longest ones -- the "feeder" roots -- are near the soil surface. When planting the tree, dig the planting hole twice the size of the rootball, and turn over soil a foot deep for that distance again further out. Incorporate some compost and other organic matter to help keep soil uncompacted. Then new roots can easily reach out into this native soil and become well-established. In addition, keep walking, decks, and other heavy-traffic and construction at least five feet away from the trunk, so feeder roots won't be harmed.
Give Green Manures Time to Decay
After clipping and digging in green manure crops, wait about two weeks before transplanting vegetable and flower seeds or seedlings. This will allow the greenery to decay sufficiently to provide nutrients to the new plantings. The heat produced from the decomposing green manure will burn seeds trying to sprout or transplants trying to get settled in.
Add Organic Matter, Not Sand, to Loosen Clay Soil
To loosen clay soil and provide slowly-released nutrition, add up to 50 percent organic matter such as leafy material, straw, grass clippings, and non-greasy kitchen vegetable scraps. Sand will not do the job -- remember that contractors mix sand and clay and water to make cement. Continue applying organic matter as mulch throughout the year. Turn it all under in the fall for a rich and friable soil the following spring.
Make Sure Irrigation Water Reaches Plant Roots
One inch of irrigated water will soak down to different depths, depending on how heavy your soil is: 12 inches deep in sandy soil, and nine inches deep in loamy soil, but only three inches deep in clay soil. Plant root zones generally reach from 2 to 12 inches down.
Start Another Batch of Lettuces!
For an attractive array of lettuce flavors, textures, and colors, choose varieties from as many different types as you can find -- dark greens, light greens, reds, and bronzes; butterhead, looseleaf, romaine, and crisphead. Plant more seeds every three weeks for continuous harvests of young, sweet, succulent leaves and heads. Or just keep harvesting only the outer leaves of the original batch you planted, and plants will continue growing until they bolt (send up their seed stalk and turn bitter). Choose varieties that are heat-resistant, bolt-resistant, and less likely to turn bitter when they mature during hot weather.