Gardening: Revitalize container plants affected by the heat

Last week I talked about how the heat was affecting some of our vegetables. This week I want to share some ideas for revitalizing container plants that have also been suffering in the heat.

Container plantings – especially those in smaller pots – are at our mercy for making sure they get enough water at the right time of the day. Hot temperatures coupled with dry winds can suck moisture out of a plant faster than the roots can channel water to the leaves. Every time a plant goes through one of these cycles, it is put under stress. Eventually, the plant will begin to shed leaves and flowers, or worse, just die.

Water container plantings in the evening or early morning, making sure the soil gets well soaked. Dry potting mixes, especially those with a high peat content, don’t readily rewet and need a slow stream of water. When the soil gets this dry, it often pulls away from the edge of the pot and the water then runs down around the root ball and out the drain without soaking in. This leaves you with the illusion that you have watered enough. Small containers may need an extra watering at midday.

All this is a lot of work. An easy solution is to put your containers on a drip line set on a timer. There are a number of kits on the market that have some kind of a drip tube that is wound around the pot or a little spray head. The pot lines are tied into a feeder line off a faucet. A timer is used to set the length of time the water is on. Mechanical timers are the cheapest but must be turned on manually for a set time. Battery powered timers can be set to come on at a specific time but are generally much more expensive.

I use a series of micro spray heads on a battery timer that’s currently set to come on every morning at 7:30 a.m. for 30 minutes. A side benefit for having them come on at that time is that I can check whether they’re functioning properly on my way to work. When the weather cools, I set them to come on every two to three days.

Container plants still need fertilizer when it’s hot, but don’t overdo it. Liquid fertilizers should be mixed at half strength and applied every two to three weeks. Granular fertilizer should be a long-lasting, slow-release type applied lightly according to the package directions. Once it cools down and the plants start pushing out lots of new growth, give them a good feeding to see them through the fall until frost.

Lastly, ragtag plantings that have been damaged by the heat or have finished blooming need to be cut back hard to stimulate new growth. Done right, the plants usually look naked when you get through with them but within a week or so, new leaves and flowers will begin to appear for another show.