DEAR JESSICA: I've been planting pole beans for 25 years. For some reason, each year I'm getting them later and later. I used to get them as early as July Fourth. Now I get them in middle to late August.
-- Sal Siino, Malverne
DEAR SAL: I had some questions, which you answered via email. Let's bring everyone else up to speed: I wondered if you were planting a different variety each year, as maturity time can vary among them. You told me you've been planting the same heirloom pole beans all along, saving seeds from one year to the next. Another consideration was the environment: perhaps trees that were small 25 years ago had grown up around the area and now are creating shade, which certainly could slow maturity. You assured me the garden gets a lot of sun, as it always has. You added that you rotate crops and incorporate compost into planting beds.
With those issues ruled out, what remains is fertilizer. Too much nitrogen can result in delayed maturity. Nitrogen is indicated by the first number of the three listed on the fertilizer package, typically 5-10-5 or 20-10-10, etc. The ratio of ingredients directs plants on energy use. With a finite amount of energy available, getting the formulation right is important.
Nitrogen stimulates plants to direct energy toward vegetative growth (growing leaves, shoots and stems), resulting in larger plants. Although large plants are nice, that growth leaves less energy available for flower and/or fruit production.
The second number relates to the amount of phosphorus in the product. Phosphorus supports root development and flowering, and helps plants transport energy within themselves.
Potassium, indicated by the last number in the trio, boosts the overall health of plants.
If you apply fertilizer to your beans, look for one with a lower first number to reduce the amount of nitrogen supplied to plants. It's important to point out that even if you're not fertilizing plants directly, nitrogen applied to a nearby lawn could be leeching into planting beds.
ELIMINATING ZUCCHINI BORERS
DEAR JESSICA: You recently wrote that the snow and cold weather this past winter likely destroyed some overwintering pests and diseases. I am wondering whether the snow and cold will have killed off zucchini borers or whether I should continue to use the insecticide on my zucchini plants this summer. I had problems in the past until a gardening center recommended the insecticide, which I would prefer not to use.
-- Connie Axelson, Oceanside
DEAR CONNIE: Squash vine borers are pests that lay tiny eggs along the lower portions of stalks, then morph into inch-long, thick white caterpillars with brown heads that bore into stalks and kill the plant while chewing their way out. They cocoon in the soil, where they often survive winter, then re-emerge in late spring as orange-and-black moths ready to repeat the cycle. Sometimes there's even a second generation in August.
It's possible the borers in your garden were killed by the severe winter weather we've had, but I can't say for sure. Keep a close eye on plants in May, when borer eggs would hatch, and at least weekly as the season progresses. If you spot any red, flattened-oval eggs, pick them off immediately.
Close inspection will reveal small puncture holes at the bottoms of stalks and stems that are infected, as well as frass, or caterpillar excrement, which resembles sawdust. Most gardeners generally don't notice until it's too late, as plants flower then simply die, seemingly for no reason.
You don't say which insecticide you've used. Btk is a safe and natural product that kills only caterpillars that chew on treated stems and does not affect plant health. It should be applied weekly for full protection.
There also are some cultural practices that can reduce squash borer populations. Your first course of action should be to rotate crops: planting zucchini elsewhere this year would deprive any surviving borers of their meals and give plants a better chance for survival. Also, be sure to clean up garden beds to remove any remaining debris (leaves and other plant parts) left over from last year's crop, as it might harbor overwintering borers.
Should you notice puncture holes on plants, slit stems open lengthwise near holes using a razor blade, and pick out the borers by hand. Then mound soil around the base of the plants to cover the injured portion of the stem. This will encourage new roots to grow, and often saves plants.