Q: I've heard that pine needles and oak leaves cause soil to be acid. Is this true? Radio caller
A: This is a gardening myth that should be put to rest. While needles and leaves from all trees may be acidic initially, they do not acidify the soil as they break down. Soil has a natural ability to buffer changes in pH. Soil acidity might increase slightly for a few weeks after leaves fall, but the acidity will go away after a few months. It's true that pines can grow in poor soil, but they didn't make the soil poor to begin with. I have research references at bit.ly/mulchacidity
Q: Every spring I plant radishes and always have the same problem. The plants look beautiful and lush but only about one in ten turn into radishes. The rest just have a red stem going into the ground. Marc Nellums, email
A: This is a common radish complaint, but the causes are multitudinous: too much fertilizer, too little sun, wrong variety, too much water or not enough space between plants. Make sure you're planting spring radish varieties, like 'Cherry Belle', 'Burpee White' or 'Icicle'. Plant in mid- to late February. Space seeds a half-inch apart and a quarter-inch deep. When leaves emerge, immediately thin the plants to one to two inches apart. Little fertilizer is needed if the spot was gardened the previous summer. You'll increase your chances for success by planting more radish seeds every 14 days until mid-April.
Q: My grandmother mentioned eating creasy greens in spring. She said they were a favorite mountain tonic. What can you tell me about them? Kylee Callaway, Augusta
A: Creasy greens, also called winter cress, are in the mustard family. The botanical name is Barbaraea verna. Mountain folk would look for them in early spring and cook them as you would turnip greens. They have a definite "twangy" taste, plus many good vitamins. The leaves grow in a rosette, similar to dandelion. I have more details plus seed sources at bit.ly/creasygreens.
Q: What are the small white flies on the back of my collard leaves? Lee Reaves, East Cobb
A: I wasn't previously familiar with whitefly damage to collards, but it turns out that this is an important pest. They suck sap from the leaves, eventually killing them. Insecticidal oil, like neem oil, is effective if you are persistent about applying it. The easiest synthetic insecticide to use is acetamiprid (Ortho Flower, Fruit & Vegetable Insect Killer). Read and follow all labels.
Q: I need to fertilize my fescue lawn. I used starter fertilizer in September when overseeding. Should this month's fertilizer include a weed killer or pre-emergent? Carmen Worthington, Gwinnett County
A: The general rule is that you can apply weed chemicals when the fescue has been mowed 2 - 3 times. If your grass is not thick and lush, I'd avoid the weed killer and stick with straight lawn fertilizer, applied at label directions.
Q: We were in Northern Ireland recently and noticed sick ash trees. Looks like their government is stepping in to control this disease. Linda Morrison, email
A: At least they don't seem to have emerald ash borer (EAB) insects in addition to the ash wilt that is spreading through the United Kingdom. EAB is killing millions of ash trees growing in the Midwest. The main source of this insect's spread seems to be infested firewood. You see signs at every nursery and along major highways to "Burn It Where You Buy It".
