Answer: I like to turn over the soil--either by hand or with a tiller--as early as possible in the spring. Just wait until the soil has dried out so it doesn't form big clumps. Tilling wet soil will compact it too much. Let the tilled garden sit for a few weeks, and till again. This will take care of any newly sprouted weeds.
It's always a good idea to add organic matter to any garden soil. Organic matter improves drainage on heavy soils, and helpswater-holding capacity on sandy soils. Incorporate compost, shredded leaves, grass clippings, well-rotted manure, or other organic matter directly into the soil when you first turn it over in the spring. (Wait a few weeks to plant if you use non-composted additions.) Then throughout the season, use grass clippings or shredded leaves as a mulch--it will keep down weeds and add even more organic matter.
Well prepared soil will be quick draining yet hold just enough moisture to keep the roots of your plants happy.
Hope you have a bountiful harvest!
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