Helping plants thrive in summer

Conditions are perfect for houseplants in July. The long days of summer give them plenty of light for growth, and they thrive on porches, decks and carports.

Summer’s high humidity and temperatures suit these tropical plants quite well. It is almost like being back in their jungle homelands of Asia, Africa and South America.

The first thing to do is get your garden hose out and wash down your houseplants while they are outdoors. A gentle spray will rinse dust and dirt from their foliage and give them a healthy shine. The water will also raise the humidity around them to 100 percent.

Watering is needed every two to four weeks in summer. This applies to houseplants outdoors as well as those stuck indoors in the air conditioning. Always check the soil with your finger before watering, because adding additional water to soil that is already moist is harmful.

Fertilizing is a summer activity, and flowering houseplants are going to put on the maximum floral display if fertilized at least once. This is particularly true of hibiscus, geranium, amaryllis, poinsettia and Christmas cactus. Foliage plants also benefit from fertilizer.

There is no better time to repot houseplants. This messy business can be done outdoors where cleanup is simple. Plants traumatized by the repotting process will soon perk up and grow new roots into the new potting soil.

Old leaves are trimmed off as they go from green to yellow to brown. This color change is natural and expected as leaves age. Your job is to pull or clip them off to clear the way for new growth.

Plants getting too big for their indoor spaces are cut back by 50 percent or more in July. This radical pruning practice stimulates an abundance of fresh leaves, making old plants look new. It works well on citrus, shefflera, ficus, dumb cane and philodendron, among others.

Roots will develop on leafy houseplant stems or slips when you stick them in pots of soil and keep them moist. These stem cuttings offer an easy way to increase your supply of plants such as weeping fig, rubber plant, geranium, corn plant, wandering jew, Swedish ivy, pothos, philodendron, arrowhead vine, dumb cane, Swiss cheese plant, Christmas cactus and wax and angel wing begonias.

Other plants will grow from leaf cuttings placed in potting soil. These include African violet, Indian rope, sedum and Rex begonia.

Baby spider plants hang on runners with roots dangling in the air. They almost beg you to cut them free and pot them up. The same is true of tiny bulblets sprouting at the base of old amaryllis bulbs.

Summer is also ideal for houseplant divisions. You can create new plants by pulling or cutting apart old specimens and potting up the individual sections. Some of the plants to divide now are snake plant, cast-iron plant, fern, peace lily, African violet and Chinese evergreen.