Although plant growth is slowing as the temperature drops, grass plants continue photosynthesizing. Applying nitrogen now boosts the photosynthesis rate and increases the amount of carbohydrates the plants can store through winter. This results in hardier plants with increased root growth and shoot density. Carbohydrates not used for immediate plant growth are stored for later use. Turfgrass with carbohydrate reserves can green up earlier in the spring and continue growth into May without additional fertilizer applications. This is beneficial because early-spring nitrogen applications tend to promote excessive shoot growth and reduced root growth. For fall nitrogen applications, 1 to 1-1/2 pounds actual nitrogen per 1,000 square feet of lawn area is sufficient. Use a soluble nitrogen carrier such as urea or ammonium sulfate so the fertilizer is quickly available because the growing season is winding down. Many turfgrass fertilizers sold in garden centers and other retail outlets contain soluble nitrogen which work well for a November application. Avoid products that contain water-insoluble nitrogen (slow release) and clean up any fertilizer that scatters on the surrounding driveways, sidewalks or streets. (Cynthia Domenghini) Garden mums (Chrysanthemum) that have finished flowering can be cut back to two to three inches. Apply a layer of mulch over the top for protection through the winter. It is also okay to leave the top growth intact through winter. This can provide some insulation for the crown, but some gardeners prefer to tidy up plant material that has died back. Regardless of fall maintenance practices, garden mums should not be allowed to dry out during the winter. If there has not been any precipitation in the form of rain or snow, it may be necessary to apply supplemental water. (Cynthia Domenghini) Keeping up with leaves dropping onto the landscape is a big job every fall. The amount of leaf cover has an impact on the underlying plants. Photosynthesis will be restricted in a lawn covered with a dense layer of leaves preventing it from storing enough energy to survive winter. Here are a few options to deal with the beautiful mess. Leaves can be added to the compost heap but it is best to shred them first. This can be done by mowing over them on the lawn and collecting them in the mower bag. They can also be added directly into the planters. Incorporate two- to three-inches of shredded leaves to the soil at a time. This can be repeated until the leaves are gone or the soil is frozen and cannot be worked. Shredded leaves can be used as mulch around trees, shrubs and perennials as well. The shredded leaves can be left on the lawn if they are not too dense. If you can still see the lawn through the leaves overtop it should be safe to use this option. As you mow, the leaf pieces will fall in between the blades of grass and eventually break down into the soil. It may require multiple passes with the lawn mower to get the leaf size small enough. It is also necessary to mow frequently to keep up with the leaf drop. Some benefits of this approach have been reported in research. Leaf mulch incorporated into lawns can help prevent weeds from germinating between grass plants. Leaf mulch has not been shown to negatively effect on turf quality, color or soil pH. If you are incorporating leaves into a cool-season lawn, it makes sense to be on a fall nitrogen fertilization program and core-aerate in the fall as well. You can mow leaves into a warm-season lawn, but wait to fertilize and core-aerate until late May or early June. (Cynthia Domenghini) As decorative pumpkins pass their prime due to time or freezing temperatures, put them to good use. Pumpkins can be cut into small pieces and buried beneath leaf mulch in planters. Due to their high-water content, pumpkins will decompose relatively quickly and contribute organic matter back into the soil. Remove the seeds before composting to avoid growing an unwanted pumpkin patch in this location next year. The raw seeds can be gathered and roasted for human consumption, or incorporated into feed for birds and other wildlife. Squirrels, deer and other animals will appreciate the meat of the pumpkin as food becomes scarce elsewhere. Farms and zoos will sometimes accept pumpkins from homeowners to feed to their animals as well. (Cynthia Domenghini) If you haven’t gotten bulbs in the ground yet, don’t despair. As long as the soil temperature stays above 40 degrees F roots still have time to develop. This means you should still have success if you plant bulbs into early November. Check soil temperature readings for the previous week at our Weather Data Library: http://mesonet.k-state.edu/agriculture/soiltemp/ Healthy bulbs should be large, firm and dormant. Do not choose bulbs that have sprouted. Bulbs need well-drained soil. Incorporate peat moss, well-rotted manure or compost into the soil to prepare for planting. Test the soil for fertility and follow recommendations from the results. You may see high phosphorus levels if you test the soil in an area that is fertilized regularly. This can be problematic because phosphorus can hinder the uptake of other essential micronutrients. In these situations, use a fertilizer that is relatively high in nitrogen such as 29-5-4 or 27-3-3. Although these are lawn fertilizers, they are suitable for this purpose as long as they don’t have a weed preventer or killer incorporated. Apply at the rate of 2/3 pounds (3 cups) per 100 square feet. Blood meal is an organic fertilizer that is low in phosphorus and can be applied at a rate of 2 pounds of 12-0-0 per 100 square feet (1 tsp per square foot). Cottonseed meal (6-0.4-1.5) can be applied at 3 pounds per 100 square feet (2 tsp/square foot) or soybean meal (7-2-1) can be applied at 3 pounds per 100 square feet (2 tsp/square foot). If a soil test is not available use a balanced fertilizer such as 5-10-5 or 6-10-4 at a rate of 3 pounds (6 cups) per 100 square feet (2 tsp/square foot). Fertilizer supplements need to be thoroughly integrated with the soil prior to planting. The depth bulbs should be planted is typically two to three times the size of the bulb. This varies depending on the species so check planting instructions for more accurate recommendations. (Cynthia Domenghini) As the first frosts of the season strike, perennials are showing signs of fall. Though we often think of fall as a time to clean up the garden and remove debris, leaving some plant material intact is okay. Ornamental grasses and herbaceous perennials can provide seasonal interest even in dormancy. Instead of removing the above-ground growth, allow the dried foliage to bring color and form to the otherwise barren winter landscape. Foliage can also provide some insulation against winter weather for the plant crown. Wildlife can benefit from seed heads left to develop on the plant as well. Two caveats are herbaceous perennials that had disease and pest issues during the growing season and ornamental grasses growing near structures. Diseased or infested plant material can spread from year to year and dried grasses can present a fire hazard. In these situations, remove the above ground growth during fall clean-up. (Cynthia Domenghini) During the growing season leaves are making food for trees through photosynthesis. Chlorophyll found in the leaves captures the energy of the sun and gives trees their green pigment. As the amount of daylight decreases and the temperature drops heading into fall, chlorophyll production slows and the green color of leaves begins to fade. Xanthophylls and carotenes which are responsible for the orange and yellow pigment are always present in the leaves but only become visible as the green fades. Tannins are also present throughout the growing season and produce brown colors. Anthocyanins create red and purple pigments and are primarily produced during the fall. The timing and intensity of the fall display varies based on types of trees and the environmental conditions. Different species will have differing levels of these pigments. Certain types of oaks and maples have brilliant fall foliage displays with varied colors while some trees will display primarily one color. Temperature, soil moisture, rainfall and amount of sunlight impact the intensity and duration of the color. Warm, sunny days encourage photosynthesis which means sugar accumulation in the leaves. Cool nights slow respiration which helps conserve sugars. The combination of these factors results in a brilliant foliage display. Cloudy days and warm nights reduce sugar accumulation and consequently result in less vibrant leaf colors. Heavy rain, hot and dry summers, and frosts/freezes all have a negative effect on the vibrancy of fall colors and length of time they remain. During this time, an abscission layer develops where the leaf petiole attaches to the branch. This barrier prevents sugars from being transported out of the leaf to the rest of the tree. Once the abscission layer is present, the leaf is ready to drop to the ground with the help of a windy gust or rainy day. If you’ve noticed the fall display in your landscape changes from year to year pay attention to the weather patterns and this should give you an explanation as to why. (Cynthia Domenghini) Houseplants require the most attention during the. During this time, they are growing more due to the additional energy generated from the increased number of daylight hours. This results in a need for more water and nutrients. As we head deeper into fall and approach winter, daylight hours decrease and plant growth does too. Consequently, the need for added nutrition and water decreases. Too much water can cause the soil to become waterlogged making it so the roots cannot take in oxygen. Pay attention to the plant needs and only water when necessary. Insert your finger about 1-inch deep into the potting soil. If the soil is dry, it is time to water. Excess fertilizer can burn plant roots. It is recommended to only fertilize sparingly in November and February (about ¼ the normal rate), and stop fertilizing altogether in December and January. (Cynthia Domenghini) |
AuthorsCynthia Domenghini runs the Horticulture Response Center in the Department of Horticulture and Natural Resources at Kansas State University. Other contributors include K-State Extension Specialists. Archives
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