Monday, August 29, 2011

Banner year for tomatoes

Although many people on the Front Range may be tired of summer heat, there is always a plus side. One is that it has been a banner summer for productive tomatoes. This is due to hot days but more so to warm nights. Many nights have been in the sixties degrees F instead of fifties as is so often the case in Front Range summers.

After a cool May and transplanting better delayed until the first week in June, some people were despairing of realizing a tomato yield due to a late start. This has obviously resolved itself and many varieties are showing good performance.

In full sun, 80 day heirloom 'Cherokee Purple' in our garden is doing as well as 73 day modern 'Big Beef'.

Three short season varieites tried this year are of note. 70 day 'Azoychka' from Russia (photo above right) is a mild acid, yellow fruited type that is producing well. A 68 day pink Asian type, 'Zhefen Short' (photo left) from China is yielding a good crop of nice plump fruit. The heirloom 75 day 'Black Cherry' (photo right) is also bearing nicely.

Shorter season types of 70 days or less including 'Early Girl' (62 days) and heirloom 'Stupice' (52 days) from Czechoslovakia (photo right) are still good bets especially if you have only part day sun or a cooler location. They bear early and can perform well in summers that don't have warm nights. Both have produced well for us this year.

Harvest from the demonstration garden at our Denver office is donated to feed the hungry. Consider donating your excess bounty to a local food pantry or soup kitchen.

Photo credit: 'Azoychka', 'Zhefen Short', 'Black Cherry', 'Stupice' tomatoes - All Carl Wilson.

Monday, August 22, 2011

Harvesting fall squash

I've received several questions about when fall squash are ready for harvest. Fall or winter squash should be harvested when fully mature which is more typically in September than August. Immature fruit have a watery flesh, don't store well and if harvested are eaten like summer squash. Not all of them will taste good when eaten immature, hubbard and golden acorn reputedly are O.K.

As fall squash matures, the flesh becomes drier and sugars develop. Both changes contribute to storing quality. Some types will store up to 3 or 4 months when harvested at the right time and stored under ideal conditions (dry and 55 degrees F). One inch of neck should be left on the fruit and it should be hard and dry when harvested.

General signs of maturity are skin that can't be easily dented with a thumbnail, color that is true to mature type, and reaching the proper number of days to harvest.

Certain types of squash have other things to look for. On acorns, the groundspot where fruit touches the ground will change from yellow to orange. Carefully turn fruit over to check being careful not to detach from the stem in case you have to roll it back to let it ripen further (photo acorn above left - still yellow: immature). On golden acorns, the groundspot doesn't show like it does on green acorns. Yellow skin should turn a deep golden yellow at maturity on these.

Butternut squash are ripe when vine growth stops and skin color changes from a light whitish tan to a deep tan (photos below - left photo immature, photo right fruit medium mature and still needs time to turn a deep tan).

Vegetable spaghetti squash are mature when they turn from a light yellow to golden yellow (photos below). Buttercup squash are ripe when dark green fruit are 5 to 6 inches across and stop growth. These are the most common varieties grown by home gardeners because their approximately 80 to 85 days to harvest makes them reliable in our climate.

Blue hubbard (blue-gray) and Boston marrow (reddish-orange) are occasionally grown. They take a full season, 110 and 120 days respectively, and are mature when vines die down.

Photo credit: Rotating acorn to check maturity, Butternut immature and medium mature, Vegetable spaghetti immature and mature - All Carl Wilson

Friday, August 12, 2011

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

Monday, August 8, 2011

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