Shortcut to raising soil's pH will upset young trees' nutrition


March 18, 2001

Q. I'm getting ready to plant some shade trees and fruit trees in my back yard, but I just got back my soil test recommendation and the pH is very low -- 5.2. The guy at the garden center said if I spread lime now it will take too long for it to actually raise the pH. He told me to put the lime right in the planting holes. Will that burn the trees?

A. You will create an excessively "sweet" soil and nutrient imbalances if you apply the recommended amount of lime directly to the planting holes. Go ahead and spread the recommended amount of lime over the entire planting area as soon as possible. It will take several months for the pH to rise to the desired level. So add and mix in one cup of ground limestone to the soil in each planting hole. This will ensure an adequate supply of calcium to the tree roots while the soil pH slowly rises.

Q. Six years ago, I planted seven hemlocks as a windbreak. Last year, two of the trees lost most of their needles by summer's end, and two others didn't look so hot. One tree blew over this winter and had hardly any roots. There are very few adelgids or scales on these trees. Could it be a root disease? They're not growing in the best soil (it stays wet), but I thought hemlocks were pretty tough. What can I do to bring them back?

A. Sounds like there may be a variety of cultural or environmental problems. This is often the case with trees that decline for no apparent reason. Actually, hemlocks are not very tough. They grow best at higher elevations on moist, well-drained sites and in partial shade. Hemlocks can't tolerate windy sites, wet soil or drought.

So your trees have experienced significant stress due to repeated droughts and poor soil conditions. The fact that one tree blew over indicates that the root systems are poorly developed. It's unlikely that your hemlocks will recover and become strong, well-established trees.


1. In honor of St. Patrick, plant seed potato pieces that are certified disease-free. Space them 12 inches apart in the row. Be patient. It sometimes takes one to two weeks before shoots emerge.

2. Overseed lawns at the rate of 3 to 4 pounds of tall fescue seed per 1,000 square feet. Apply a starter fertilizer and water seeded areas thoroughly twice a day to promote strong, early growth.

3. Clean leaves and debris from ponds and resume feeding your fish when water temperatures stay in the 50s.

Backyard Q&A is by Jon Traunfeld, regional specialist for the Home and Garden Information Center, Maryland Cooperative Extension Services of the University of Maryland. For additional information on these questions, or if you have questions of your own, call the center's hot line at 800-342-2507, or visit its Web site at / users / hgic.

Baltimore Sun Articles
Please note the green-lined linked article text has been applied commercially without any involvement from our newsroom editors, reporters or any other editorial staff.