|
| Acid loving plants... Soil prep the key! - Tuesday, October 17, 2006 at 15:55 |
| Rhododendron, Azalea, and Clethra all prefer to be grown in a lower soil pH (acid soil). The addition of peat moss is an excellent soil amendment when planting, but may not lower the pH of the soil enough. Yellowed leaves or interveinal chlorosis (yellowing between the veins of the leaf) will be exhibited by the plants that are being grown in soil with a pH that is too high. Lowering the soil pH to make it more acid.... If your soil needs to be more acidic, sulfur may be used to lower the pH if it is available. To reduce the soil pH by 1.0 point, mix in 1.2 oz of ground rock sulphur per square yard if the soil is sandy, or 3.6 oz per square yard for all other soils. The sulphur should be thoroughly mixed into the soil before planting. Sawdust, composted leaves, wood chips, cottonseed meal especially peat moss, will lower the soil pH. For existing plantings... I have found that a really good product is "Ionate" or regular soil sulphur available at (purchase online from our website!) most garden stores both products are sold in small bags like flour or sugar comes in...Look for them when you are there. A nice fall application of either product put down now will have the winter to break down and begin to lower the soil pH sooner. I usually like to lightly top dress the root zones around these plants about every other fall. You can usually tell by looking at the summer foliage color if the soil needs treatment or not. Of course, the best method is to have the soil tested, but the old eyeball method works just fine. If things are not broken, I don't fix them. What about Mir-acid you ask?...works fine as a quick fix...a liquid that works very quickly to get rid of chlorosis, but does not last long. Fall is also a great time to apply a new layer of organic mulch to all plantings..new or old, as it prevents the soil from freezing for a longer period and you will get some nice root growth in the fall. Tim |