Watering in the heat -- it’s an art
JULY IS AS CLOSE TO a month off as a gardener gets. Aside from watering and weeding, it’s best to leave the garden alone. It’s just too hot, and most plants are simply hanging in there, waiting for cooler weather. If you want to take a vacation, now’s the time. Just find someone who can take care of the watering.
Watering wisdom
On really hot afternoons, it’s OK to cool stressed-out plants by spritzing them with your thumb clamped over the end of a hose. But don’t think that counts as watering. Summer irrigations should be deep and thorough.
You want to get water deep enough into the soil to prevent rapid evaporation. Then you don’t want to water again until the top inch or so dries out. That’s how you discourage disease and encourage plants to root deeply, safe from temperature fluctuations.
Even lawns, often watered daily, do best with twice-a-week irrigations. Don’t wean plants too quickly if you have been over-watering. Give them a chance to adapt to the new regimen.
Like birds in a cage
Plants confined in containers need more frequent watering and fertilizing than those in the ground, sometimes much more. After all, they are completely dependent on the gardener.
Potted plants in the sun must be watered every day in summer; some may need water twice a day. They also need fertilizing once or twice a month (follow label directions) because they cannot forage.
Timing it right
It’s important to irrigate in the morning, as early as possible. Timers should be set for about 4 a.m., when there is no breeze to blow water off course or scatter sprinkler mist. Watering in the morning also allows foliage to dry before nightfall, which helps prevent disease on lawns or roses. It also makes it uncomfortable for slugs and snails to crawl around on the dry ground.
Try to do chores such as weeding in the morning when it’s cool. Save planting for late in the day, so they have all night to settle in.
Planting options
If you really need to plant, consider putting things in pots (where they can be watered often), in the shade (where the shade-tolerant will not dry out so quickly) or in the vegetable garden. To keep crops coming, you can plant these vegetables: snap bean, beet, carrot, corn, leaf lettuce (near the coast, or in partial shade) and radish.
It’s too late to start most summer vegetables as they will not have enough time to mature. But about mid-month, coastal gardeners can start a few winter crops: broccoli, cauliflower and Brussels sprouts.
Tomato troubles
If it gets too hot, tomatoes will stop fruiting. When it cools a little, they will start again, so don’t give up. Watch for those black, spiny nymphs of the keelbacked treehopper (nymphs are about 1/8 of an inch long). They cluster on stems and drain them like little vampires. Ants often spread the young, and they are found on many kinds of Solanaceae, including ornamental white potato vines and cestrums.
Soap sprays do them in and won’t poison fruit. Also watch for the big, blimp-sized (or so it seems) tomato hornworms that can defoliate stems. Because they’re green, they’re hard to spot so watch for the black droppings.
Don’t over-water tomatoes; some gardeners near the coast don’t water them at all once they get going. Too much moisture brings on disease, splits fruit or rots roots.
Some like it wet
Aquatic plants -- those that grow either completely submerged or with their roots in standing water -- are summer’s big planting opportunity since they are seldom found at other times of the year. Many can be grown in big pots with drainage holes plugged, or in small ready-made ponds.
Water lilies and lotus are the showiest of aquatic plants, but they also need the most room and water depth (at least 18 inches). Lilies also need fertilizer in summer, so if plants seem to be slowing down, look for special pellets that can be pushed into the soil around roots.
Snip, snip
If you haven’t already, cut off blackberry canes that fruited this spring. They will not produce again, and you need to make room for the new canes that are growing longer by the minute. To make way for new growth, cut back spring flowering perennials such as hellebores and euphorias.
On bloomed-out alstroemeria, don’t cut stems off, but give them a quick yank and they will cleanly pop off.
