Answer: Good drainage is essential for healthy apple tree growth. If the soil is mostly clay, it holds a lot of nutrients, but drainage is often a problem. An increase in humus is the best way to acheive long-term drainage improvement, but planting your trees on a slope will help, too. Add lots of organic matter, such as compost, rotted leaves, grass clippings, etc. to the planting site, keeping in mind that tree roots will take up at least as much room underground as the crown of the tree occupies above ground. For this reason, you'll probably want to choose dwarf or semi-dwarf varieties, so their root systems won't be too inhibited by the clay soil.
Other needs of apples include full sun and attention to disease and pest control. Your agricultural extension office (ph# 302/697-4013) can help you with a list of varieties that do best in your region - their list should include disease-resistant variteties. If you're interested in earth-friendly insect and disease control methods, let us know, and we can help. Enjoy!
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