It is easy to forget or ignore how the summer sun can affect plants over an entire season. Prolonged heat stresses garden plants and lawns out, and can quickly undermine all of the hard labor you put into your vegetables and greenery in the spring. To enjoy the beauty and bounty of summer flora all season long, it pays to take some precautions to protect plants from extended periods of heat. Round out your summer garden care with these tips for keeping it green.
1. Mulching Matters
Plants that have shallow surface roots will typically do just fine in warm weather. A true heat wave, however, can turn the top layer of soil to dust, stressing root systems beyond their capacity to cope. The answer is mulch. The benefits of sufficient mulching are threefold (at least). First, mulch reduces the amount of direct exposure soil has to the sun, helping it to retain some surface moisture even as the mercury climbs. Secondly, mulch reduces evaporation, increasing the effectiveness of your daily watering sessions. Due to its moisture-retaining qualities, mulch potentially reduces the frequency that plants need watering. Thirdly, mulch protects against wind, which combines with hot temperatures to over-dry soil. When selecting mulch for your vegetable garden or bedding plants, go for light-colored mulches. They tend to work best because they reflect heat better than darker materials. Effective mulches include:
- Grass clippings
For vegetable gardens, let cut grass dry out for a day or so after mowing to reduce the amount of nitrogen. While nitrogen is an important nutrient, it can support plant growth at the expense of fruit and vegetable production.
This makes excellent mulch due to its light, reflective color. Be sure to get straw and not hay, which may carry and introduce unwanted seeds into your garden.
This is a great choice for moisture retention and weed control around shrubs and other landscape plants. However, it may be too acidic for vegetables. Some bark mulches have been shown to carry weed-producing seed, but in general, it forms an effective and attractive layer for beds and borders.
2. Watering in the Heat
In a period of extended high temperatures, thoughtful and responsible watering is essential to keep plants thriving. Water is lost at the surface of the soil as well as through the leaves, so sufficient watering is critical. Timing plays a large role. Effective summer garden care during a heat wave involves early morning watering. There is less loss of moisture to evaporation in the earlier, cooler part of the day. In addition, with morning watering, you can avoid the scalding damage to leaves that can occur under the hot midday sun. Morning watering also reduces the slug population and the growth of fungal disease, as conditions stay drier overnight. That said, there are times when you may need to water again in the evening.
Water conservation is an important consideration in a heat wave, and certain states have water restrictions in place during the summer. For this reason, hand watering may be a better option that sprinklers. Ambient heat causes water from a sprinkler to evaporate more quickly than water directed from a hose. Soaker hoses are often the best choice, as water is channeled directly where it needs to go. Soaker hoses may be placed under mulch and out of sight, and regulated on a timer just like a sprinkler.
3. Made in the Shade
Garden centers package and label protective coverings by size and shade factors. A shade factor indicates how much sunlight the material blocks. Typically, shade cloths can protect plants from 25 to 90 percent of the sun’s rays. The choice depends upon the hardiness of the plant. The object of a shade cloth is not to completely cover the plant, but to limit its exposure to all-day sun. It is important to maintain good airflow around the plants, and to make sure the shades can stay put under windy conditions. Thrifty gardeners may rig their own shade covers with netting or row covers, although these homemade versions will lack the shade factor of the ready-made material.
4. Help Plants Help Each Other
Transplants are particularly vulnerable to the effects of heat. To give transplants a fighting chance in hot and dry conditions, use the buddy system. Find a spot in the garden where tender starters may get a little shade from a taller, more established neighbor. The larger plant can provide some protection from the wind, too.
Ideally, the plant you use to provide protection for the transplant will be one that you will pull out after the smaller plants become mature enough to benefit from more direct exposure to the sun. In this way, early vegetable crops such as peas can give way to the midseason delights of summer squash and beans. You can even plant successive crops of the same vegetable, pulling up the mature plants after production slows down. A staggered planting schedule may require a bit of planning, but you will be rewarded with continuous growth throughout the season.
5. Let Lawns Go a Little
This can be a tough one for homeowners who like a fairway-fresh lawn. Holding off on the mowing and leaving your grass a little taller helps the soil retain the moisture it needs to keep the lawn lush, even in the heat. Three inches is the minimum to provide enough shade to be of benefit. Set the mower to six inches during a drought.
Try to avoid the temptation to overfeed your lawn during a hot spell. The ability for root systems to take in nutrients is greatly diminished during a heat wave. Fertilizing in the heat is not only a waste of product, it may also more harm than good. You are much more likely to get the results you are after if you wait until the temperature drops a bit before you supplement the soil. With some preparation and patience, summer garden care will yield a full season of enjoyment under even the warmest conditions.