Prickly Pear

Through the dormant months give bright light and only enough water to keep the pads from shriveling. Let the soil dry fully between waterings the rest of the year. Given genuinely sharp drainage the plant tolerates a lot of water, but in heavy soil that holds moisture, water little. Prickly pear stores its own water in the pads, so its roots have no defense against soil that stays wet. Root and stem rot from overwatering is the way most backyard plants die, not cold or drought.

In warm weather cut a pad at least six months old off at its joint, stand it in a dry shaded spot for one to two weeks until the cut face forms a hard callus, then set it upright just one inch deep in a half-and-half mix of soil and sand. Stake or wedge it with rocks so it stays upright, and do not water it in. Roots form in about a month; water once then, and let it dry out between waterings after that. An uncallused cut is an open wound on a stem that is over 90 percent water, so a pad planted wet or planted deep rots before it can root. The callus seals it, and pads root far faster than seed, which takes three to four years to reach flowering.

Decide what you want off this plant. If you are growing it for nopales, feed a high-nitrogen fertilizer through the growing season to push tender new pads. If you want tunas, switch to a no-nitrogen fertilizer such as 0-10-10 about once a month instead. Nitrogen buys leafy stem growth at the expense of flowers, and every flower is one fruit, so a nitrogen-fed plant gives you pads and few tunas. Dropping the nitrogen pushes the plant toward bloom.

When you are shaping the clump, thinning a crowded center, or removing a damaged pad, always make the cut at the narrow joint where one pad meets the pad below it. Do this in warm weather, and let removed pads dry out before you replant or discard them. A cut at the joint is a small wound that callus closes over quickly, while a cut across a pad leaves a wide wet face that stem-end rot moves straight into. Rot at cut tissue is the main thing that ruins harvested and pruned pads.

Take the small, tender young pads while they are still soft and thin, cutting them free at the joint where they meet the supporting pad with a sanitized knife. Harvest between mid-morning and mid-afternoon. A well-tended plant can be cut for pads up to six times a year, so keep taking the new flush as it comes rather than stripping the plant at once. On a newly planted pad, wait several months before taking anything. Acid content in the pads is lowest from mid-morning to mid-afternoon, so midday-cut nopales taste better than dawn-cut ones. Young pads are the most succulent and carry the fewest spines. Cutting a young plant too early costs you every future harvest, because the pads you remove are the branches that would have borne them.

Look over the pads for conspicuous white cottony masses. Scrape one off with a knife and crush it on paper - a deep red smear confirms cochineal scale. Light colonies do negligible damage and need nothing. Only if the plant is heavily colonized and declining, prune the worst pads off at their joints and discard them, blast the rest with a high-pressure hose nozzle, and then spray insecticidal soap on the scale bodies the water has exposed. The white wax is the insect's shelter, and it sheds sprays as well as it sheds predators, so soap applied over intact wax accomplishes nothing. Stripping the wax with water first is what makes the soap work. Multiple generations run through a warm season, and the mobile crawler stage is how they reach the next plant.

Watch the fruit for its glochids falling away on their own - that is the ripeness signal. Twist each tuna off the pad rather than pulling it. Tunas are borne on mature pads, generally the second or third pad to form. Each fruit holds its perfect stage of ripeness for only about a week, so check the planting every few days once the first glochids start dropping. Prickly pear fruit does not continue to ripen once harvested, so a tuna picked early is a tuna that stays sour. Pulling instead of twisting tears the stem end, and damage to the peel and stem end is what lets decay pathogens in - shelf life is short at best, on the order of eight or nine days, so torn fruit is fruit you lose.