By Eri Matsumura | Fort Collins Nursery
It’s the second half of summer. The sun is hot, the air is hot, and everything is hot. These prolonged hot days are very stressful for plants to endure, especially if they are younger and working on getting established in our gardens. A heat wave will disrupt your normal gardening routine, so it is important to be adaptive and intentional to help your plants survive the upcoming heat. The general concept during these hot stretches is to avoid adding more stress to your plants. We want our plants to use all their available energy to survive the intense heat.
Don’t Fertilize
Adding nitrogen will push out new leafy growth, and adding phosphorus will push out flowers. This can exhaust plants, causing them to spend energy making new leaves or flowers and to spend more energy trying to sustain the new growth.
Don’t Prune
A hard cut back or pruning more than 20% of the plant can add stress, as it will need to spend energy on healing the wounds. However, small rounds of grooming and deadheading spent flowers is okay. If the plant has a broken stem or branch, cutting it off can actually help the plant prioritize its energy to support its healthy parts.
Don’t Transplant
Say it with me: “Don’t add more stress!” Exposing and agitating the root ball to divide or transplant is an extremely stressful event. This should be avoided entirely until cooler temperatures arrive, or at least until the cool hours of the evening.
Don’t Overwater
It’s easy to think that all plants will need more water when prolonged hot days are in the forecast. However, the watering rules are always the same; make sure to inspect the soil and only water when the top inch has dried out. It’s best to do a long, thorough watering in the early morning, rather than frequent, shallow waterings. This will encourage deeper root growth as the plant pushes its roots down to cooler dirt, as opposed to the roots staying small and shallow. The only exceptions are plants like hydrangeas and ferns; high-moisture plants might need a second watering on hotter days. Container plants like annuals and vegetables may also need a second watering as well.
Do Mulch
Mulching the exposed dirt around the plants with bark mulch, straw, or grass clippings helps the soil retain moisture and stay cooler. Be sure to leave space around the crowns or stems of plants to avoid diseases and rot.
Do Set Up Shade
Consider hanging up shade cloth or sticking an umbrella in the ground to help minimize direct sun exposure. Plants like herbs, some vegetables, or young starter plants could benefit from protection from the most intense sun, especially in west-facing locations where the afternoon sun is the strongest.
Above all, remember that heat waves will pass and cooler mornings and rainy afternoons will visit soon. Drink water, stay cool, and be kind to each other.