We just passed the Summer Solstice, and with the longest day comes warmer weather. As things heat up, here are some tips for supporting your plants during the summer heat waves, while saving water.
- Mulch, mulch, mulch. Whether you use bark, shredded leaves, or wood chips, a thick layer of mulch will help the soil retain moisture, keep roots cooler, and control weeds that compete for water. Remember to keep mulch at least 2” from the base of all plants and 6” from tree trunks.
- Compost, compost, compost. When you add organic material to the soil it can hold more water. It also helps to open up the soil allowing roots to go deeper, and better soil nutrition helps plants produce better with less water.
- Protect plants in containers. Containers can heat up fast, and roots will literally bake. Try to protect your containers with shade cloth, or group them together in a spot that gets afternoon shade.
- Control weeds. Unwanted weeds compete with your plants for water. Keep them under control with drip irrigation and a 3” layer of mulch.
- Avoid fertilizing during heat waves. Fertilizer promotes growth which demands more water to form new leaves, which in turn need more water to survive. If you do need to fertilize, use a slow release, organic fertilizer to discourage excessive growth.
- Start seeds in trays. A flat will require far less water to germinate seeds than watering a raised bed where seeds have been directly sowed.
- Irrigate early in the day. When you water in the cooler part of the day when winds are lighter there is less evaporation.
- Consider a Smart Controller. With a controller on your irrigation system you can program the time of day your water runs, create zones by plant water needs, and even set the water to increase on extra hot days, or decrease on those foggy, cooler days.
- Transition to low-flow irrigation. A drip system or micro-sprayers allow water to penetrate more deeply with less lost to run-off.
- Water deeply, less often. Use soaker hoses and let the water penetrate the soil to 12”. This will encourage deeper roots and plants will have better heat tolerance. Use a soil moisture meter to decide when to irrigate again, or squeeze the soil in your hand. If it sticks together, it is still moist; if it crumbles and falls apart it’s time to water again.
- Think native. As plants decline, consider replacing them with native plants. These species have adapted to our Mediterranean climate and once established, can survive with little summer watering.
Help Desk of the UC Master Gardeners of Contra Costa County (RDH)