, Newburyport, MA

July 10, 2013

Tim's Tips: Plants need extra attention in heat

Tim's Tips
Tim Lamprey

---- — The only good thing about this weather is that any of the tropical flowering plants you may have are probably the happiest plants in your planters!

One of the hardest things to do during a heat wave is get out into the garden. No one feels like weeding, fertilizing or watering. However, all these things need to be done to keep your plants healthy.

Ideally, watering your plants should be done first thing in the morning. Plants take up water better in the morning. When you water, it is important to apply enough water to get moisture down into the top 6 inches of soil. If you have plants in containers, there needs to be enough water added to the container so that water drains out the bottom.

If the soil in the container has gone very dry, it tends to pull away from the sides. If this happens, you need to apply some water to the soil and then allow time for it to absorb that water. You should wait a few minutes and then apply some more water. You may need to do this multiple times until the soil has absorbed enough water to expand back to the sides of the container.

You will find that tomato plants grown in containers tend to outgrow the container unless it is large enough for the large root system that a mature tomato plant will possess. Many times in the spring, you will get a tomato plant in, say, a 1-gallon container, which is about an 8-inch pot. For a tomato plant to grow properly, it needs to be in a 5-gallon pot, which would be about 14 inches in diameter.

A while back, Dave from Newburyport emailed in a question about a tomato plant that wasn’t doing so well. I suspect that the plant was in too small of a container. At this point in the season, it’s hard to transplant any tomato plants into bigger containers without setting the plants back in their growth cycle. When planting into containers, keep in mind the ultimate size of the plant and use a large-enough container.

The hot weather we are having is not that unusual. Don’t count on a cool summer to allow your plants to survive in smaller containers. Choosing a large-enough container for any vegetable should be done in the spring.

If your vegetable garden or flower beds are drying out quickly, it’s a good idea to apply at least 2 to 3 inches of mulch onto the surface of the soil. Keep the mulch away from the stem of the plant. The mulch will help keep the soil cool and hold moisture in. Sometimes, just adding a layer of mulch onto the soil will help cut back on the number of times you have to water your gardens.

During the hot and humid weather, dew settles on the leaves of your plants. You may also have a sprinkler system that comes on at 3 a.m. to water the plants. You may also find that it is necessary to water plants in the evening.

In all of these cases, the leaves of your plants are going to be wet in the nighttime hours. Wet leaves at night are the perfect breeding ground for fungus diseases on your plants. As much as you may hate to go out to the gardens and poke around, you do need to see if fungus diseases are beginning.

If you catch the diseases at an early stage, you can control them. If you wait until a disease is widespread, you may not be able to control it, and, ultimately, the plants can die.

My apologies to Vanessa, a Newburyport resident who wrote in to ask about a problem weed in her yard. Sorry it has taken so long to let you know about the weed that you cannot control.

The weed she described is called Japanese bamboo. It was planted many years ago as an ornamental hedge. It has a massive root system that is impossible to dig out of the ground. The best time to control this plant is in the late summer or early fall when the plants form seed heads.

If you spray the leaves with Roundup at that time, the weed killer will be taken down to the roots and will kill them. If you use Roundup, just remember that any spray that gets on desirable plants will also kill those plants.

Well, that’s all for this week. I’ll talk to you again next week.


Tim Lamprey is the owner of Harbor Garden Center on Route 1 in Salisbury. His website is Do you have questions for Tim? Send them to, and he will answer them in upcoming columns.