Q: How do I get my compost pile hot enough to kill weed seeds? A: If you add grass clippings or weeds to your compost pile, chances are you'll wind up with a few weed seeds in the pile. The only way to kill them is to get the pile cooking so it reaches an internal temperature between 140 and 160 degrees. First you'll need a pile big enough to generate that kind of heat. A good-sized pile is at least four feet square at the base and three to four feet tall. Make sure it has a mix of nitrogen- and carbon-based raw materials in it. Without moisture, the pile will just sit there, so water it regularly to keep it moist. Turn the pile every week to ensure it gets plenty of oxygen. You can cover the pile with a tarp to hold the heat in. Your pile should get hot enough to kill weed seeds if you follow those steps.
Q: Last spring I planted several container-grown perennial flowers. They did okay, but they didn't really get much bigger than they were in the container. What's the deal?
A: Assuming you fed and watered them regularly, all you need to do is be patient. There's something called the perennial rule of three in the plant world, which means that during their first year of growth, many perennials don't grow much at all. During the second year, they grow a little more, and by the third year they really take off. At that point the plants are well-established, meaning they can take care of themselves for the most part.
Q: I've noticed that you recommend tree rings around newly planted trees. At what point can you get rid of them?
A: I do recommend tree rings--areas around the tree where the surrounding sod has been removed and a thick layer of mulch applied. They give the tree a better chance of surviving during the first few critical years of growth by reducing competition for nutrients from grass and by holding in moisture. Once the tree is well-established--after three or four years--you can remove the mulch and let the grass grow back up to the base of the trunk. You can also leave rings in place, but I think trees in the landscape, like those in the wild, look a lot more natural without the rings.
Q: How far out from most trees do the roots actually grow?
A: For decades we've been told that tree roots grow out from the base of the tree to the tip of the tree's widest branch, an area known as the drip line. They actually extend much farther than that, perhaps as much as 50 percent farther. As much as 90 percent of those roots grow within the top 12 inches of soil.
Q: My dwarf pear trees keep growing straight up rather than out. I've tried to remedy the situation by pruning them, but it doesn't help. What can I do?
A: Many pear trees naturally assume a columnar shape, but you can fool Mother Nature with a limb spreader, which you can make at home. Cut a few sections from a garden stake at random lengths, say, six, eight and 10 inches. Then cut V -shaped notches in both ends of the stakes. Locate the branches on your trees that you want to spread, and gently wedge the stakes between those branches. You'll want to leave the spreaders in place for about a year, after which the limbs should assume their altered position permanently.
Q: How do you grow the miniature corn often found in Asian dishes?
A: Growing baby ears of corn is simple, and you can use any variety of sweet corn. The trick is to plant corn close together and to harvest the ears earlier than usual. For example, if you want full-size corn, you space the plants about a foot apart and harvest after the silks have turned brown. If you want mini-corn, cram three or four plants into the same foot, thus stunting their growth, and harvest just before the silks turn brown.
Q: I love caladiums, but since they're not hardy in my area, I have to buy new ones every year, which gets expensive. Is there any way to store them over the winter?
A: Yes. Lift the bulbs in early fall just as the foliage begins to fade, and let them dry indoors in a cool, dry place with plenty of air circulation. Pack them in a box full of dry peat moss, and store at temperatures between 50 and 60 degrees. This technique also works for dahlias, gladiolas and tuberous begonias.
