Vegetable and Fruits

Asparagus care

If you have followed all the advice on asparagus care you will have asparagus ferns turning yellow by the autumn (October time). I never cut the stems back for they hold snow which is good for the bed.

Depending on what variety of plant or seed you have chosen you will either have all male plants or a mix of male and female asparagus plants.

Only the female plants produce berries, and this uses up some of their energy and as a result they have a lower yield of spears by as much as 1/2 or 1/3rd compared to their male equivalents.

My final piece of advice on asparagus care is weed control, the bain of my life! I’m afraid I hate weeding, but that is just what you are going to have to do. You really don’t want to be hoeing unless very shallow and light as the asparagus roots are quite close to the surface and easily damaged.

If you feel you need to use a weed killer, then you are going to have to be very careful. Use a glycophosphate based product and apply it carefully to the leaves of the weeds avoiding the asparagus. Read the instructions carefully especially as concerns the use on vegetable crops. Apply in late fall after the bed has turned yellow.

Shade Trees and Shrubs

Trees that are Stressed by Drought

Trees signal their water deficit through several symptoms. The most common changes in appearance are lighter green to yellow-green foliage, leaf scorch around the margins, wilting leaves and dropping them prematurely. Conifers will often produce an abundance of cones the second year of a drought. Trees that are stressed by drought are also more susceptible to insect borers and canker diseases.

Water Needs: Tree size & species

Just how much water does an established tree need during our hot summers? This depends on several variables, but two key ones are the size and species of tree. Almost all the water absorbed by a tree on a summer day is lost out of the leaves through transpiration. This process moves water from the roots, up through the trunk and branches and releases it as water vapor from small holes in the foliage. Only one or two percent of the water is used for meeting the needs of the tree for photosynthesis and other functions. While water is “lost” through transpiration that does not mean it was wasted. The water vapor from the leaf helps cool the foliage surface. A mature elm tree may have more than 150,000 leaves so the tree may transpire more than 100 gallons of water in a single sizzling summer day!

There are also differences among the many tree species in the amount of water they transpire. Conifers with their thicker, waxy needles lose less moisture than a broadleaf tree such as a linden or maple with their wide, thin foliage. However, the differences among tree species is not as important as its size. The larger the tree, the more water it requires.

Water Management

Trees required water during the summer and the general rule-of-thumb is they need about one inch of water per week. Unfortunately, rains are not that dependable in South Dakota and we can get three inches one day and nothing for the next two months.

Ideally this amount of water is provided to the tree every week, rather than double or triple the amount every two or three weeks. The water should also be applied slowly so that it soaks into the ground rather than runs off. The area to be watered should be from the trunk to a distance out equal to about half the height. While tree roots often extend as far out as the tree is tall, most roots are closer to the trunk.

Check to see if you are adding this amount, place an empty coffee can within the sprinkler zone and run the sprinkler until you have about 1 inch of water in the container. Also check to be sure the water is infiltrating the upper foot of the soil as this is the zone for most absorbing roots. After the first watering or two, dig a narrow hole by hand to a foot deep and check to be sure the soil is moist. If not, additional water may need to be applied or the water applied at a slower rate.

Garden Pests

Squash Bugs

Avoid using mulches and clean up any debris around plants to eliminate shelter for squash bugs. Practicing crop rotation can greatly reduce their numbers as well. However, rotations will not completely keep squash bugs from showing up because of their ability to fly in from other sites. If you have infestations every year, consider using an early trap crop such as blue hubbard squash. Squash bugs tend to colonize the first suitable host in the environment, and a trap crop can serve as a lure that can then be treated and destroyed to greatly reduce squash bug populations. Simple fertilizing and watering of cucurbits is also advantageous, as it will make the plants more tolerant to feeding injury.

Early detection is the key to managing a potential squash bug infestation is early detection. When plants are young, check the stems and leaves for egg clusters and crush any that are observed. It is impossible to eliminate all of the eggs this way, but it is a good preliminary strike that helps reduce populations later in the year. As the season progresses, continue to watch for nymphs and check cucurbits for wilting or discolored leaves, as these are signs of a possible infestation.

Physical removal of squash bugs may be effective if only a few plants are infested. For heavier infestations or if more plants are affected, insecticide treatments are recommended. Insecticides should be applied early in the season to manage nymphs because the adults are more resilient and difficult to kill. Several products can be used for squash bug management including carbaryl (Sevin), permethrin, and spinosad. For best results, make sure to get good coverage on the undersides of the leaves where squash bugs typically like to hide. If plants are flowering, be aware of pollinators and try to apply insecticides in a manner that does not directly harm them.