Landscape Soil – Preparing for Planting
Q: Our developer has left our subdivision with only compacted clay for yards. Any holes we dig hold water for 2-3 days! The developer planted fifty trees last winter, 30% died, 30% are declining and the rest are barely growing. We bought twelve beautiful trees at the Trees Atlanta sale but are afraid to plant them. If we dig the large diameter but shallow planting area recommended and then dig down 2 -3 ft on one corner of the planting area, do you think this would keep the tree roots from setting in water? Or do you have any other suggestions? We have to do better than that.
A: It took a bulldozer about a day to clear away the good soil Mother Nature had deposited in your yards over the past hundred years. Now your ground resembles what was there before complex plants began growing on earth: hard clay subsoil. So you are faced with the task of imitating a million years of nature’s work – and doing it in a weekend!
To that end, a rented rear-tine tiller is a God-send. For each tree, just tear up the clay in a circle ten feet wide. Once the clay is pulverized, you have to keep it that way. There’s nothing better than adding a soil conditioner like Nature’s Helper or Clay Cutter. Mix two – three bags into the rototilled area for each tree. While you’re at it, mix in a pint of lime and a quarter cup of 0-46-0.
If you REALLY want to go top drawer, add some mycorrhizae innoculant to the soil as well too. Mycorrhizae are fungi which exist naturally in most soils. They help tree roots absorb moisture and nutrients. Your clay likely has few mycorrhizae and could benefit from their addition. The only Atlanta mycorrhizae source of which I’m aware is Ben Meadows Company (770-479-3130)
Lastly, though your back will be aching, dig a dry well at least two feet deep and a foot across at the lower edge of each planting area so water can drain there. Fill the well eighteen inches deep with coarse gravel, cover the gravel with black weed-preventer fabric (to exclude soil) and add topsoil on top. Those trees will be SOOOOO proud to have you as caretaker!