Vegetable Garden Tips for July

Dragging the Hose

When rain becomes elusive in July – and it likely will, despite the current run of soggy days, I drag the hose around the garden.  Often the water is turned on to a mere trickle and I move the hose end from spot to spot as I pull weeds, letting water seep deep into the soil around individual blueberry shrubs.  Or I might hook up the main hose to a soaker hose winding through the strawberry bed or raspberry patch, letting water ooze into the soil for two or three hours.

The rules of watering are simple.  First and foremost, when you water, water deeply, then allow the soil to dry at the surface before watering again.  Your best measure of when to water is your index finger: stick it in the soil and if it doesn’t find water, drag the hose.

A simple soaker hose is an effective method of watering a bed of strawberry plants.

Second, apply water at the feet of garden plants, keeping the foliage and fruits dry.  This is critical to keeping tomato leaves blight-free and squash fruits from growing gray beards.  A drip irrigation system, even a simple soaker hose stretched between plants, really pays off here.

Third, if you must use an overhead sprinkler – and we do when it gets really hot and everything is too dry at once – water early in the morning.  This will allow the foliage to dry quickly.  Water left on leaves at the end of the day is an invitation to fungal diseases, including blights and mildews.

Fourth, keep a layer of organic mulch on the soil to reduce evaporation of water from the soil.  A three- to four-inch layer of straw or shredded leaves works well in this regard and also prevents the rain, when it finally comes, from splashing fungal spores onto the lower leaves of plants.

Finally, weed, weed, weed.  Unwanted plants compete with crop plants for water.  Much of our garden time in July and August is spent pulling weeds, trying to get them out when they are small.  Mulching makes this task less time consuming.

Pulling weeds will keep you in touch with the soil’s need for water.  If dry soil is pulled up with the weed, it’s time to water.

Containers scattered about the garden, as their plants become pot-bound, need watering every sunny summer day.  I either drag the hose from pot to pot or, if some of the potted plants look hungry, I mix up a half-strength fish emulsion solution in a two-gallon watering can and carry it around the garden.  In either case, I water slowly until I see excess water leaking out of the drainage holes.  Moving some of the pot-bound plants into more shade can lighten the load a bit.

There is time in July to drag the hose, or allow it to drip water into the soil while I pull weeds.  It is contemplative work that puts me in close touch with the plants.  Marjorie is likely there too, and Berry, the cat, both good company.  Perhaps this is why the drip irrigation system is still in the box.

Intensify your scouting

As garden plants mature during July, herbivore populations can peak to the point of standing room only on the underside of leaves.  The smart gardener will set aside time specifically for scouting, inspecting plants for insects or the damage they have done.

Japanese beetles can be controlled by knocking them off of the foliage into a pail of soapy water.

Make your scouting trips early in the morning when the insects are sluggish.  Check the undersides of bean leaves for Mexican bean beetles and inspect cucumber and squash plants, both leaves and flowers, for striped cucumber beetles.  Examine eggplant leaves for Colorado potato beetles.  Inspect raspberry leaves and grape leaves, as well as roses and other ornamentals, for Japanese beetles.  Carry a small pail of soapy water with you and pick or knock the beetles into it.  With heavy infestations, I have dispatched an entire beetle-infested leaf to the pail.

I am ambivalent about the use of yellow sticky traps as a means of herbivore monitoring or control.  Beneficial insects, including herbivore predators, may fall victim to these traps as readily as the herbivores, so I recommend using them only as a last resort.  For example, if you are faced with an explosion of striped cucumber beetles, place a few yellow sticky traps in the midst of the plants and closely monitor what is being trapped.  Discontinue their use as soon as possible and return to hand-picking.

Harvesting Garlic

After harvesting your garlic, hang the bulbs on the porch or other covered area to dry.

Sometime in July or August, depending on the season’s weather, garlic leaves will begin to slowly die back, an indication that harvest time is near.  When the leaves are gone, or nearly gone, dig the bulbs and brush off the soil, spread them out on the porch to dry for a week or so, and then braid them for winter storage.  Don’t forget to set aside some of the largest bulbs for planting in fall.

Tomatoes

Watch for spots and yellowing on the lower leaves of your tomatoes.  They are early signs of diseases such as septoria leaf spot and early blight.  Preventative measures include removing the infected leaves – bag them for the trash or burn them, but do not put them on the compost pile – and spreading a straw mulch over the soil to minimize splashing of spores onto the leaves during rain or irrigation.

Removing all of the lower branches is an effective way to prevent foliar diseases in tomatoes.

Some gardeners remove all of the leaves below the first flower, infected or not, in order to minimize these disease problems.  This makes for an odd-looking tomato plant, but is very effective, particularly when combined with the straw mulch.

Blossom-end Rot: a Physiological Scourge

Another common problem of tomatoes, eggplants, and peppers is blossom-end rot, named for the dark, sunken, leathery blotches that develop on the fruit’s blossom end (the end opposite the stem).  It is not caused by a fungus or virus, but by a deficiency of calcium in the developing fruit that typically occurs during periods of stress, particularly drought stress.  It can also result from wide fluctuations in soil moisture levels and when plant growth is overstimulated with too much nitrogen fertilizer.  Also, heavily pruned tomato plants, such as those tied to stakes, often succumb to blossom end rot – another good reason to cage, rather than stake, your tomatoes.

There is no cure.  Avoidance of this physiological stress involves watering during dry periods, applying mulch around plants to maintain consistent levels of soil moisture, and using moderate levels of nitrogen fertilizer.

Tomatoes planted in cold soil tend to develop blossom-end rot on the first fruits with the problem disappearing as the soil warms.  Wait until soil temperatures have settled above 60 degrees before setting out transplants.

Cultivating too close to plants and too deep can damage water-absorbing roots.  Pull weeds around tomatoes by hand and when they first emerge.

Also, maintain the soil pH at 6.5.  Liming to raise the pH will also supply calcium and increase the ratio of calcium ions to other competitive ions in the soil.  Foliar applications of calcium have little affect due to poor uptake by the plant and minimal translocation to the fruit.

Onions

Onions appreciate an organic nitrogen boost in July.  Apply a handful of cottonseed meal or soybean meal to each 10 feet of row.  This light feeding will result in larger bulbs.  Too much nitrogen, however, will produce bulbs that do not store well through the winter.

Summer Squash

As summer heat and humidity intensify, check summer squash fruits for blossom blight, fuzzy growth at the tips of fruits that lead to rotting of the fruit.  Control this problem by improving air circulation, removing excess foliage and all weeds, and thinning overcrowded plants.

Powdery mildew is sure to infect leaves of cucumber and squash in late summer, particularly on crowded plants. Spraying the leaves with a baking soda solution before the disease occurs may help.

You can prevent powdery mildew from infecting squash plants with weekly sprayings of a baking soda solution.  Make the solution with one tablespoon of baking soda per gallon of water, adding a half teaspoon of liquid dish soap as a spreader-sticker.  Apply once a week in mid-summer and only on well-watered plants.  Spray the plants early in the day, not in full sun.  Discard any unused solution.  Try the solution on  a few leaves first to make sure your variety of squash is not super-sensitive.

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About Reeser Manley

I was born in Laramie Wyoming but moved to the southeast at an early age. I was educated through my B.S. in Biology in the Columbus, Georgia area, then crossed the Chattahoochee River to earn my M.S. in Botany at Auburn University. For the next ten years, I worked as Horticultural Manager for the George W. Park Seed Co. in Greenwood, S.C. At 40 years of age, I decided to return to graduate school and in 1994, I earned a Ph.D. in Horticultural Science from Washington State University, Pullman, Washington. Fast forward through 10 years at university (7 at UMaine, Orono) and you find me teaching high school science in Eastport, Maine, the edge of the world, and writing a weekly garden column for the Bangor Daily News. My new book, The New England Gardener's Year, a Month-by-Month Guide for Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, and Upstate New York”, will be published later this year by Cadent Publishing. You can learn more about the book by visiting its Facebook page: http://www.facebook.com/pages/The-New-England-Gardeners-Year/187285218055676.)