Category Archives: gardens

Tomatoes and Heat

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Here in the Inland Northwest, we have gone from 50 something degrees to 99 degrees in a matter of days it seems. Not only does that play havoc with our human bodies but it can have consequences in our gardens.

The common miconception is that tomatoes love heat, the hotter the better. Not so much. High temperatures can cause several problems with tomato production. One of them is “tomato blossom drop.” The tomato blossoms “dry up and fall off the plant before a fruit is formed.”  

 “Tomatoes grow best if daytime temperatures range between 70 F and 85 F. Tomato plants can tolerate more extreme temperatures for short periods, but after several days or nights with temps outside the ideal range, the plants start to focus on survival not producing fruit. High nighttime temps are even worse than high daytime temperatures because the tomato plant never gets to rest.”

 Another tomato response to extreme heat involves its leaves. Just as they respond to very cold temps and lots of moisture with their leaves, you will  notice that some tomato varieties also respond to heat by curling their leaves. That’s a defensive mechanism that attempts to slow transpiration (evaporation from the leaf surface) of water from plant to atmosphere. 

 Specific temperatures at which blossom drop begins will vary from variety to variety. If you experience this, all is not lost, they will eventually snap out it. Water thoroughly early in the morning or put a drip system on at night to keep them well hydrated. Mulch to help retain their moisture. And pray for more temperate weather!Image

Another Trouble Afoot – Leaf Curl/Roll

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We have been having huge shifts in temperature lately. From 80’s to the 50’s and lots and lots of rain. Our tomatoes are reacting to these changes on an individual basis. some of my varieties, actually most of them, are doing well. A couple have leaf spots (I’ll do a separate post of that at a later date), my “Cougar Red” has some curled, rolled leaves (other than that it is healthy). I have done some research on the latter and this is what I’ve found:

“Leaf Roll:

During very wet seasons, tomato plants frequently show an upward rolling of the leaflets of the older leaves. At first this rolling gives the leaflet a cupped appearance. Later, the margins of the leaflets touch or overlap. The rolled leaves are firm and leathery to the touch. One half to three-fourths of the foliage may be affected. Plant growth is not noticeably checked, and a normal crop of fruit is produced. Frequently leaf roll occurs when tomato plants are pruned severely, and it is very common when unusually heavy rains cause the soil to remain moist for long periods of time.

To prevent leaf roll, keep tomato plants on well-drained, well-aerated soil, and protect them from prolonged periods of heavy rainfall if you can.”

Also this: (Univ. of Colo.)

“Leaf roll, or leaf curl, is a physiologic distortion that may develop with periods of cool, rainy weather. It cause the lower leaves to roll upward and become thick and leathery. Leaf roll does not affect plant growth or fruit production and requires no treatment.

Leaf Roll

Herbicides can distort the foliage and fruit of tomatoes. They are especially sensitive to 2,4-D. Damage can bend the leaves down, causing cupping and thickening. New leaves are narrow and twisted and do not fully expand. Fruit may be catfaced and fail to ripen. Exposure can occur when herbicides are applied to lawns for weed control and the spray “drifts”. Resultant fumes can also effect the plants for several days after treatment. Clippings from grass that has been sprayed with a herbicide should not be used as mulch in the vegetable garden. If the exposure is minimal, the plant will outgrow the injury. Be sure to water the affected plants thoroughly and often.”

I guess I will have to wait and see how they turn out. In the meantime, the “Cougar Red” is in it’s own pot and segregated to be on the safe side.

Flea Beetles are on the loose in the Inland Northwest

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Flea Beetles, A common problem this time of year. It has come to my attention that they are afoot. If your leaves have what looks like little shot holes you might/probably have flea beetles. They seem to attack the lower leaves first. Here is a link ot a site that gives you good information as to what they looks like, how they overwinter and what to do about it.

http://www.ext.colostate.edu/pubs/insect/05592.html

Imageflea beetle damage