K-State Research and Extension

Q: We have been getting more rain lately than we are used to, what potential effects is all the standing water having?
A: Waterlogged soils push out oxygen that roots need to survive. Some plants have mechanisms to provide oxygen to the roots even under saturated conditions but most of our vegetables and flowers do not. The longer these plants are subjected to saturated soils, the more likely damage will occur. Usually, as long as water drains away within 24 hours, the impact on plant health is minimal. However, shallow, stagnant water under hot, sunny conditions can literally cook plants, reducing survival time to as little as a few hours.

In regards to the safety of eating produce from a garden that has been flooded, standing water should not cause a safety problem as long as the aboveground portions of the plant remain healthy. Do not use produce from plants that have yellowed. Also, using produce flooded with water contaminated with sewage (lagoon) or animal manure can also be dangerous. The safest approach is to discard all garden crops that have been in contact with such water. Certainly, leafy vegetables should always be discarded. However, you may eat fruit from such crops as tomatoes, peppers, eggplants, sweet corn, squash, cucumbers, and similar vegetables that develops after the waters have subsided as long as the fruit is not cracked or soft. Always wash vegetables thoroughly before eating.

Under the cool conditions of early spring, turfgrasses can often survive several days of flooding. However, during hot, sunny conditions with shallow, stagnant water, lawns may be damaged quickly. This situation often occurs when shallow depressions in a lawn allow water to pool. Note such areas and fill in with additional soil once the waters have subsided. Trees differ markedly in their ability to withstand flooding. Some trees have mechanisms in place to provide oxygen to the roots of plants with water saturated soils and others do not. However, most trees will maintain health if flood waters recede in 7 days or less. It also helps if water is flowing rather than stagnant as flowing water contains more oxygen. If the roots of sensitive trees are flooded for long periods of time, damage will occur including leaf drop, iron chlorosis, leaf curl, branch dieback, and in some cases, tree death. Try to avoid any additional stress to the trees this growing season. Ironically, one of the most important practices is to water trees if the weather turns dry. Flooding damages roots and therefore the root system is less efficient in making use of available soil water. Timely waterings are vital to a tree’s recovery.

Soils often become compacted and crusted after a heavy rainfall. This also can restrict oxygen to the roots. Lightly scraping the soil to break this crust will help maintain a healthy root system and therefore, a healthy plant. Be careful not to cultivate too deeply as shallow roots may be damaged. If you think the excessively wet weather will continue, bedding up the rows before planting even just a couple of inches, will improve drainage and allow for better aeration.

Q: Rabbits seem to be eating my freshly planted garden as fast as I can get it in the ground. What can I do?
A: Rabbits in gardens are a perennial problem because of the wide variety of plants they can feed on. This time of year, they gravitate to young vegetables and flowers. But there are some vegetables that are rarely bothered including potatoes, tomatoes, corn, squash, cucumbers, and some peppers. The question is how do you protect other, more susceptible plants? Fencing provides a quick and effective control method. The fence does not need to be tall; 2 feet is sufficient for cottontails. But the mesh must be sufficiently fine (1 inch or less) so young rabbits will not be able to go through it. Support for the fence can be supplied by a number of products, but electric fence posts work well.
Often fencing is not an acceptable choice because it affects the attractiveness of the garden. Other ways to control rabbits including repellents, trapping and shooting. Repellents are often suggested for control but often do not last long and require frequent reapplication. Also, many are poisonous and cannot be used on plants or plant parts destined for human consumption. Live traps can be used to collect and move the rabbits to a rural area several miles from where they were trapped. A number of baits can be used to entice the rabbit to enter the trap including a tightly rolled cabbage leaf held together with a toothpick. However, rabbits often avoid baits if other attractive food is available.
Another possibility is to use a motion-activated sprinkler. These are attached to a garden hose and release a short burst of water when motion is detected. Contech, Orbit and Havahart are suppliers and each is advertised as protecting up to at least 1,000 square feet. Shooting is another possibility when it is safe and legal to do so.

Q: Someone gave me a rhubarb plant, what do I need to know about transplanting, growing and eating this crop?
A: Rhubarb is a perennial vegetable that is grown for its large, thick petioles or leafstalks. It is known for its acid flavor and used in sauces, jellies and pies, either alone or in combination with other fruits.
Rhubarb grows well in many soil types, but it thrives in rich, well-drained loam soils. In most Kansas soils, generous applications of organic matter should be incorporated before rhubarb is planted. Using 50 to 100 pounds of barnyard manure or a similar organic material per 100 square feet of garden area is beneficial. Because rhubarb is a perennial, it should be located to the side of the garden or in an area not disturbed by yearly tilling. An established planting should be fertilized each year using 4 to 5 pounds of 1-10-5 (or the equivalent) per 1,000 square feet broadcast over the plot and worked into the soil early in the season before growth begins. Adding 2 to 3 pounds of ammonium nitrate per 1,000 square feet over the plot after the spring harvest season will provide nitrogen for good summer foliage growth.
Rhubarb should be planted in the early spring. In Kansas, the suggested planting time is mid March to early May, about the same time as Irish potatoes. Rhubarb is propagated by planting pieces of older crowns or roots. The pieces are taken from dormant three-year or older crowns. The crowns may be purchased from garden dealers or seed dealers, or dug from a healthy, established planting during the dormant season. If you dig your own crowns, split them into pieces with each containing one large “eye” or bud. Each crown should produce four to eight pieces suitable for planting. Crowns should be kept moist until planted and should be solid, not spongy. Plant rhubarb in a shallow trench so each bud is about one half to 1 inch below the soil surface. Plants should be 2 to 3 feet apart in the row, and if more than one row is planted, 4 to 5 feet between rows. Fill in the trench to cover the crowns and firm the soil around them. Make sure there is not a “depression” along the row so excess water drains away quickly. Compared with most other vegetable crops, relatively few varieties of rhubarb are available. The two varieties that have been used most widely in Kansas are Canada Red and McDonald.
Rhubarb will lose productivity after 5-10 years, with very productive plantings requiring more frequent rejuvenation. Dig and divide crowns in the early spring by cutting older crowns into sections with a sharp cleaver or axe, leaving at least one bud or eye on a root section. Probably no other single factor affects home gardeners’ success with rhubarb more than harvesting too much or too long. Rhubarb is a perennial crop, and its vigor and strength depend on stored food reserves that it accumulates during the previous season. For this reason, it is good to limit harvest the first several years. Rhubarb should not be harvested at all the first year, and only a few stalks should be taken the second year to insure a well-established planting that will last for many years.
Some years, it is common for rhubarb to produce a large, yellow seedstalks during the growing season. Seedstalks should be broken off and removed as soon as they form. Removing seedstalks will cause more food to be stored in the crowns and roots encouraging more leaf growth.
CAUTION: Rhubarb leaves contain oxalic acid that may cause lesions in the mouth if eaten, so only the stalks or petioles should be eaten. After harvest, rhubarb stalks should be stored in the vegetable storage area of the refrigerator and kept moist until used.