Squash viruses

Several viruses affect squash including squash mosaic virus and cucumber mosaic virus. Aphids transmit the viruses from infected plants that can include weeds such as common lambsquarters, kochia and others.

You may discover viruses as we did recently in our yellow zucchini planting by spotting one plant with light green, mottled leaves in a sea of healthy. dark green leafed plants. (Click photo to enlarge). Leaves often have a mosaic pattern and may be distorted, have deep lobes, or appear string like and thin.











Fruit can appear small, deformed, mottled, have ring spots or exhibit color breaks and may develop warts. In our planting the affected fruit (photo left) look quite different than normal yellow zucchini (photo right). The different viruses produce different symptoms depending on the stage in which the plant is affected and several viruses can affect the same plant.

Do plant virus resistant or tolerant varieties when available. Purchase seed from a reputable supplier and use care in saving seed. Manage aphids to keep numbers low. As soon as diseases appears, remove plants like we did. Viruses can be mechanically transmitted so wash hands and tools before working with healthy plants. Control nearby weeds that may harbor viruses. There are no pesticides to control viruses.

Photo credit: Virus mottled leaf plant stands out, Virus distorted fruit, Normal yellow zucchini fruit - all Carl Wilson

Tomato pruning debate

I've had several conversations about removing tomato suckers with people recently. Suckers for those who don't know are the shoots that grow between the tomato leaf branch and the main stem. If you choose to remove them, do so when they are young rather than letting a large shoot develop. The question is should you remove suckers or not?

There certainly are some pluses to this growing technique: easier to train on a support whether stake or cage, ability to plant more plants closer together and easier access to harvest fruit. See photo of tomato in a pot with slim form produced by having all suckers removed. The alternative is not pruning which usually is done by letting tomatoes run on the ground. With large, 3 to 4 feet wide, sturdy cages, not pruning is also often practiced.

One of the disadvantages of removing suckers is exposing fruit by having less leaf cover. This can increase the chances of sunscald (photo). Sucker removal carried to the extreme probably limits the photosynthetic capacity of the plant particularly with some less robust tomato varieties.

You also can use some of both techniques along the way. Removing suckers at first and then slacking off and letting them grow later produces more leaf cover to protect fruit from sunscald. What works for you?

Whether you are pruning or not, you should have fruit beginning to ripen. Nighttime temperatures are already beginning to drop into the fifties along the Front Range. The August transition to fall will also see more daytime temperatures in the eighties. For warm weather loving tomatoes, fruit development should be well along at this point in the growing season.

Photo credit: Tomato plant with suckers removed, Sunscald on green tomato fruit - both Carl Wilson

Seed or transplant for Fall

Now is the time to finish seeding or transplanting 50 to 60 day crops to mature in Fall. We just finished installing kale, red and golden beet transplants (photos). Even though it's hot now, these crops and others including lettuce will grow and be of good quality as they mature in cooler fall temperatures.

Planting a second crop where spring crops leave "vacancies" increase yields from a given square footage of soil during a growing season. Rotate crops and don't plant same family plants such as kale following cabbage. We planted beets following lettuce and cabbage, and kale following beets.

This higher demand on garden soil is equivalent of a full season crop such as tomato or potato. It requires adequate organic matter and fertility to meet the needs of the second crop so do be sure your soil is prepared to handle succession planting.

Photo credit: Transplanted kale, red beet, golden beet - all Carl Wilson

Hail recovery hope

To encourage those with gardens struck by hail, this post features pictures from a previous year's hailstorm. While chances of recovery depend on the extent of the damage, plants can surprise. Fruiting vegetables always seem to sustain the worst damage, particularly the big-leafed vegetables like squash and pumpkins. Roots escape underground and regrow. Leafy vegetables generally come back.

These photos of tomatoes and straightneck summer squash are from a July 21 hailstorm. White hailstones are visible in tomato photo. Click on photos to see enlarged view.



The photos below show plants August 17, about a month later. The Yellow Taxi tomato is sparse and shows hail-nicked foliage but did ripen fruit. The summer squash put on an amazing amount of growth and more fruit.

Photo credit: All five photos in post - Carl Wilson

Use of Mid-summer Transplants

While many people think of transplants as only a May start-of-season planting technique, they can also be useful in midsummer for planting crops for fall harvest. In midsummer you don't even need a greenhouse to grow them!

There are always two ways to plant - direct seed or transplants. Mid-July is a rough date to have 50 to 60 day vegetables direct seeded to mature for fall. Using this target date, you can plan whether transplants or direct seeding will best work in your crop scheduling following spring crops.

Perhaps you have a crop growing that won't be harvested in the end of July and direct seeding another would not allow it to mature before frost. Answer is grow transplants. Or perhaps you have difficulties directly seeding the garden because of wind and sun, soil crusting or other physical soil condition, inability to frequently water to germinate seed, garden pests on young seedlings or whatever reason. Transplants may work better for you.

Growing transplants in pots placed on the ground (or bark mulch) as pictured works well. Floating row cover fabric thrown over the pots and tucked under the trays conserves water and helps seeds to germinate. Remove when seedlings have begun to develop true leaves or leave on to protect from birds and insects. Grow for 4 weeks or so and you are ready to gain a jump on the fall harvest season by transplanting into your growing beds.

Photo credit: Trays of pots growing on bark mulch, Kale (bottom) and beets (top) grown as midsummer transplants - both Carl Wilson

Cool to Hot update

Flea beetles are a concern on tomatoes that were set out in May before weather was settled. These plants were stunted from the cold nights and have struggled to begin rapid growth even with the last week of hot weather.

Key to overcoming flea beetle feeding is to promote rapid growth of transplants and seedlings. Flea beetles jump from the soil and attack lower leaves first (photo right). If a transplant grows rapidly as did this tomato set out June 5 (see photo left), they overcome injury. For details and control suggestions for flea beetles that infest tomato family, cabbage family and other plants, see the CSU Extension fact sheet Flea Beetles.

Cilantro flowering has promoted more questions than usual this season. The quick change from cool to hot weather caused plants to rapidly develop flower stalks. Both temperature and day length influence flowering. In hot weather during the long days of summer, cilantro rapidly produces flower stalks with ferny foliage as opposed to the desireable flat leaves (photo shows both).

Plants induced to bolt produce flowers and set seed in four to six weeks from time of sowing. If you purchase transplants, they can quickly start to flower too. Grow plants in cooler shade to delay flowering. Sow a succession of cilantro seed every few weeks through the summer to produce a constant supply of the herb. In cooler spring weather, cilantro will keep in the leafy stage weeks to a month longer.

Note that if plants go to seed, you can make coriander spice from grinding the seed instead of harvesting cilantro leaves.

Photo credit: Flea beetle injury lower tomato leaves, Tomato transplant outgrowing flea beetle injury, Cilantro - All Carl Wilson