As summer gets into full swing here in the Pacific Northwest, I remember (generally after our first day in the 90’s) that my plants in the house and in the garden need a little extra attention staying cool if I want them to thrive throughout the next few months of heat.
My top 4 tips for keeping your plants happy in hot weather:
1. Water deeply
As soon as you wake up, with a cup of coffee in hand, get hydrating! The morning is an ideal time to water deeply as it allows time to penetrate the soil deeply to keep it cool throughout the day while giving the plants time to dry off before nighttime temps drop again. Wet leaves at night encourage fungal disease growth so it's best to leave them dry before heading off to bed. The goal is to water deeply, for longer amounts of time-not just a sprinkle, but instead, a nice, long drenching.
Why is drenching so important? Two reasons, first when you water your plants more deeply, it gets past the top soil and hydrates where it is most accessible to the root system. Second, it keeps the overall temperature of the soil cooler for longer as the sun bakes the top layer of soil and dries it out but takes much longer to affect the soil beneath. I recommend you water your garden and most houseplants (with the exception of cacti and succulents) a few times a week during the long, hot days of summer.
Adding a few inches of mulch on top of the soil not only keeps the weeds away it also feeds your soil while it breaks down, and it keeps your plants hydrated and cooler for longer periods of time. For outdoor plants I recommend straw (not hay, it contains seeds) and leaf mulch both ideal for your edible garden while decorative rocks, pebbles, sand and moss are wonderful ways to top off and help retain moisture in your houseplants.
Another method of mulching is by planting other smaller plants or edibles in the soil around your taller plants to create ‘living mulch’. You can plant sedum and smaller succulents that spread well around your houseplants and ornamentals and actually, for your edible garden too! However, for your edible garden, I recommend an even better method that leads me to the next tip...
When you place smaller plants like lettuce, radish, basil, strawberries or spinach, under larger plants like tomatoes or corn, you not only create a more aesthetic garden, you’re also helping smaller veggies stay cooler during the heat of the day, while allowing the tomatoes and corn to soak up all the beneficial heat and direct sunlight they need to thrive. This method accomplishes many things at once: providing a living mulch you are covering the soil with other plant matter which in turn controls unwanted weeds and insects, all while extending the life of plants like lettuce and spinach that tend to bolt (“bolting” is when a plant goes to seed while becoming bitter and unappealing to birds and insects that might otherwise feed on the leaves while the plant is trying to reproduce).
4. Shade cloth
My other trick is hanging shade cloth over the south and west facing bedroom windows for my houseplants and erecting a tent for part of the garden during the crazy hot days, especially the days that sneak up and surprise you! Just last week, for example, we had a few days in the 90’s while the rest of the month we were hanging out around 65-75 degrees. No big deal for the houseplants but in the garden, a few hot days can cause all the spinach and lettuce types to bolt and, (speaking from experience) way too many heads of lettuce in need of immediate harvest! One year I had over 100 heads in one week begin to bolt. Everyone in the neighborhood had salad for dinner. Throwing a quick shade cloth tent up during those days helps keep greens cool and can prolong the salad season!
Stay cool my friends!
My happy garden with heritage plantings