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The mention of black walnut trees makes many gardeners groan, because all of the plants parts, from leaf to root tip, contain a substance called juglone that causes severe stunting of many plants, including tomato. In fall, black walnut hulls become a car-bashing, foot-bruising problem, too. After you harvest the nuts, you're left with that pile of tarry hulls. Is it really safe to compost them?

Thanks to on-farm research done by Chris Chmiel in Athens, Ohio, the answer is yes. Looking at all the…

Blister beetles (Epicauta vittata and other closely related species) appear in swarms in summer, just as tomatoes, beans and other crops start looking good. This native species does one service — the larvae eat grasshopper eggs — but then the adults strip leaves from a dozen different plants. Hand-picking them can be dangerous, because a toxin in the beetles’ bodies can irritate the skin. Blister beetles often drop to the ground and play dead when disturbed, so the best way to collect them is to…

The answer to both questions is yes, but the key factor is “local.” Fruit tree varieties vary tremendously in how many chill hours they require, which is the average number of hours when temperatures are below 45 degrees. If you plant a low-chill variety, it may start blooming so early in spring that the flowers and fruit are damaged from freezing. Varieties with high-chill requirements fruit poorly when grown in climates where winters are mild.

Local nurseries stay in business by selling climate…

The bean you are seeking is probably the white tepary bean (Phaseolus acutifolius), which has been grown by Native American tribes of southern Arizona and northern Mexico for thousands of years. The tribal name Papago (“bean people”) was used for many years, but in the 1980s, the tribe’s actual name, Tohono O’odham (“desert people”), became popular instead. The 24,000 people of the Tohono O’odham Nation grow several types of dry-climate beans, but if the bean you seek is small and flattened, it …

CCA-treated wood, often called pressure-treated wood, is very common, and you are right to be concerned about it affecting your garden. The three main chemicals that can leach into your soil — copper, chromium and arsenic — are probably concentrated within a few inches of the base of your fence. Studies that analyzed the chemical content of soil inside raised beds framed with CCA-treated wood found high concentrations of arsenic in soil within 2 inches of the wood and normal levels of arsenic 2 …

If slugs are a huge problem, you need to remove their habitat by raking up your mulch in spring and composting it. Then, start your garden in open soil, and wait until early summer to add a fresh blanket of mulch.

You still may have problems because your soil may be well stocked with slug eggs. A few years ago, a U.S. Department of Agriculture scientist found that crabgrass contains a substance toxic to slugs. Since then, many backyard slug slayers have experimented with crabgrass cookies, which …

Many people use shredded non-glossy paper in mulch or compost, where it typically degrades in a single season. Since paper is a wood product, you should regard it as a high-carbon soil additive, similar to sawdust. When using it to make compost, you will need to add plenty of nitrogen-rich green material. When using it as mulch, most gardeners cover it with a layer of organic mulch, such as leaves.

Laser printers use toner rather than ink, which usually contains plastics or waxes. The residual ef…

All baby peppers start out some shade of green and change color as they mature. Some peppers stay green until they mature to yellow or red; others may turn white, lilac or purple before maturing to red or yellow. You can eat peppers at whatever stage you prefer, but the colo…

If you are simply cleaning up a wild patch, cut out the old, dark brown canes (stems) at the ground, and then throw some compost over the bases of the newer canes, which are usually green or reddish brown. If the new canes are so big and unruly that they bite you when you get near the patch, use pruning loppers to top them back to about 8 feet. They will then grow short lateral stems, which often bear a good crop of berries.

Anytime from early spring to early summer is good to dig and move black …

Instead of trying to dig and move your patch, concentrate on reclaiming what’s there. Asparagus persists for decades, and the amount of work it will take to rejuvenate your plot is nothing compared to digging it up. Asparagus can outcompete weeds, but your spears will be bigger and more numerous if you limit weeds and fertilize the patch twice a year, once in late spring and again in early winter.

Begin by doing some serious weeding. Every time there is a drenching rain, go out and pull some weed…