Frequently Asked Questions: Home Landscaping/Turfgrass

Turfgrass/Diseases

• Mushrooms are growing in a circle in my yard. How do I get rid of them?
   
• My lawn has dead grass and I think a fungus is killing it. What do I spray?
   
• Patches of my grass appear to be dying. The grass is yellow to straw color and moldy. The problem began as soon as the snow melted. How can I save my grass?

Turfgrass/Horticulture

• When is the best time to fertilize my lawn? How many times a year should I fertilize?
• What fertilizer should I use? Is a liquid better than a granular? Is organic fertilizer better?
• How should I deal with grass clippings? Don't I have to collect them?
• How can I control weeds: dandelions, creeping Charlie, clover, crab grass, quackgrass?
• What grass is best in Minnesota?
• Can I grow zoysia plugs here?
• How late can I sod?
• When can I plant grass seed?
• Which is better, seeding or sodding?
• How much black dirt do I need to bring in before seeding and sodding?
• How can I get rid of weeds without using chemicals?

Answers: Home Landscaping/Turfgrass

• Turfgrass /Diseases
  1. Mushrooms are growing in a circle in my yard. How do I get rid of them?
     Questions to ask: Do the mushrooms grow in a complete circle or are they randomly appearing around the yard? Is grass in or around circle dead or alive?
     Mushrooms that grow in a circular pattern in the yard are called fairy rings. They live on dead organic matter in soil or thatch. Usually there is dead brown grass just inside the mushroom ring. Fairy rings are difficult to control. Management strategies designed to mask symptoms include watering the soil, removing mushrooms, fertilizing properly and aerating soil. It is also possible to try and eradicate the problem by removing soil, fumigating and reseeding; however, this is usually not required. (Dial U Brief: Fairy Rings, 1990.)
      
  2. My lawn has dead grass and I think a fungus is killing it. What do I spray?
     Patch diseases are a common problem in turf. Patch disease can be caused by a number of different fungi and, therefore, can be difficult to identify. These diseases are usually the result of poor site conditions or poor cultural practices. Management strategies include thatch management, aeration, fertilization and mowing practices. A fungicide is very seldom recommended and should be used only when cultural practices have not been effective. (Turf Patch Diseases, MES-FS-3034-A, Revised 1997; and Dial U Brief: Cultural Practices to Help Manage Disease Problems in Home Lawns.)
  3. Patches of my grass appear to be dying. The grass is yellow to straw color and moldy. The problem began as soon as the snow melted. How can I save my grass?
     
     The problem is snow mold, caused by fungi that can tolerate very low temperatures, just above freezing. There are two different types, pink or gray. These fungi do not occur every year and are associated with deep, early snow covers that prevent the ground from freezing. The disease will become inactive as temperatures rise and the grass dries. Chemical control is not usually required in the home lawn. Rake infected areas to speed drying of turf. Help minimize future problems by avoiding excessive nitrogen fertilizer in the fall, avoiding a thatch build up, mowing the lawn through fall and spreading snow to help speed up the melting process. (Dial U Brief: Snow Molds in Lawns, 1991.)
  
  Turfgrass/Horticulture
  4. When is the best time to fertilize my lawn? How many times a year should I fertilize?
     Apply most fertilizer in late summer and fall rather than spring. Always water the lawn immediately after fertilizing to release nutrients and prevent burning. How many times you fertilize depends on the type of grass plants and how much care you decide to give your lawn.

     For a high-care lawn with improved Kentucky bluegrass and improved, turf-type perennial ryegrass, watered during summer: fertilize May-June, August, September, October-November. If you leave mowed clippings on the lawn you can eliminate the September application. For a low-care lawn with common bluegrass and fescue, and little or no summer watering: fertilize August and October-November, or only once in September if you leave clippings on the lawn. (Fertilizing Lawns, MES AG-FO-3338-B, Revised 1990.)

      

  5. What fertilizer should I use? Is a liquid better than a granular? Is organic fertilizer better?
     A soil test is recommended to determine the ratio of nitrogen, phosphorus and potassium you need in a lawn or garden fertilizer. Liquid or granular: It makes little difference to plants whether nutrients are applied in liquid or dry form if you water fertilizer off leaves and into the soil soon after application. (Fertilizing Lawns, MES AG-FO-3338-B, Reviewed 1990.)

     Is organic fertilizer better? All fertilizer types essentially do the same thing, add nutrients to soil. When properly applied, use of fertilizer generally involves no risk to humans or other animals. Synthetic fertilizers are usually cheaper, easier to apply, and faster acting. Organic fertilizers (e.g., Milorganite, manure) are often bulkier, release nutrients more slowly and are less useful as a source of nutrients. However, as they break down they add organic matter, which improves structure of soil and its ability to hold nutrients, water and air. They are particularly useful for newly planted grass seed. (Characteristics of Natural and Manufactured Fertilizers for Lawns, MES AG-FS-5774-A, 1993.)

      

  6. How should I deal with grass clippings? Don't I have to collect them?
     You can leave grass clippings on the lawn if you mow regularly. Mow often enough so no more than one-third of grass height is removed with each cutting. For example, if desired height is two inches, cut grass when it's no more than three inches high. Grass clippings less than one inch long filter down to soil surface and decompose relatively quickly. Remove longer clippings as they appear unsightly and can shade or smother grass. (Lawn Clipping Management, MES AG-FO-3915-B.)

      

  7. How can I control weeds: dandelions, creeping Charlie, clover, crab grass, quackgrass?
     The most effective method of controlling lawn weeds is to maintain a dense and vigorously growing turf cover. Often weeds can be controlled by altering cultural practices to favor grass plants such as frequency of fertilizing, and mowing height and frequency (see Questions 4, 5 and 6).

     Pulling weeds by hand is effective in small lawns, but chemical control is sometimes necessary. Always read and follow directions on label.

     Control perennial broadleaf weeds such as dandelion, plantain and thistle after they are up and growing with a selective, post-emergent herbicide such as 2,4-D. Early fall (Aug. 15-Oct. 15) is the best time to apply, although you may apply during May. For other broadleaf weeds, creeping Charlie, chickweed, clover, henbit, knotweed, mallow, spurge, yarrow, use a mixture containing the phenoxy-type herbicides, 2,4-D, MCPP and dicamba (Trimec, found in Weed-No-More) and apply in early fall. Dicamba can damage tree and shrub roots so apply carefully.

     For annual weeds such as crabgrass, use a selective, preemergence herbicide that affects germinating seeds. Apply between May 5 and 20 in Twin Cities area, two to three weeks before weed seeds germinate. Quackgrass can be controlled only with a nonselective herbicide, such as Roundup, which kills all plants. Spot treat only, because this herbicide will kill grass. Apply when weeds are actively growing. (Weed Control in Lawns and Other Turf, FS-1137-A, Rev. 1994.)

      

  8. What grass is best in Minnesota?
     Kentucky blue grass, fine fescue and some perennial rye grasses are recommended. When choosing grasses, consider these questions. Sunny or shady? High or low maintenance? For sunny locations that receive a lot of wear, mixtures of 50 percent improved Kentucky bluegrasses and 50 percent perennial ryegrasses are best. For shady locations, look for a seed mixture made specifically for shade; it will contain fine fescues along with some shade-tolerant Kentucky bluegrasses. For low-maintenance turf, a mixture of Kentucky bluegrasses and fine fescues will offer a durable lawn. (Seeding and Sodding Home Lawns, MES FS-5775-A, Revised 1995.)

      

  9. Can I grow zoysia plugs here?
     Zoysia is a very poor choice for Minnesota. It is a warm-season grass that can survive Minnesota conditions, but tops turn straw-color with the first frost and usually do not green up again until late spring. (Seeding and Sodding Home Lawns, MES FS-5775-A, Revised 1995.)

      

  10. How late can I sod?
      You can sod any time after the ground thaws in spring right into autumn. The limit on fall sodding is the amount of time sod has to develop roots before the ground freezes. The later sod is laid, the more risk it will suffer damage if there is an open winter with poor snow cover. (Seeding and Sodding Home Lawns, MES FS-5775-A, Revised 1995.)

       

  11. When can I plant grass seed?
      The best time is late summer, mid-August to mid-September. That's when conditions are most favorable for germination and growth, and fewer weed seeds are germinating that could compete. Seeding can also be done in spring, but weeds and high summer temperatures reduce success. If you apply a herbicide to your lawn in the spring, you must wait until late summer to plant grass seed. (Seeding and Sodding Home Lawns, MES FS-5775-A, Revised 1995.)

       

  12. Which is better, seeding or sodding?
      Both methods have pros and cons. Advantages of seeding: more grass types and varieties available, less expensive, stronger root system development initially. Disadvantages of seeding: it takes longer to establish a lawn, timing is limited to late summer or early fall, and moisture is critical for young seedlings. Advantages of sodding: rapid establishment, relatively weed-free in the beginning, good for slopes and areas prone to erosion, can be laid any time during growing season. Disadvantages: It's more expensive, and there is little choice of grasses, especially for shade tolerance. (Seeding and Sodding Home Lawns, MES FS-5775-A, Revised 1995.)

       

  13. How much black dirt do I need to bring in before seeding and sodding?
      It depends on composition of your soil. The best type of soil is sandy loam, which is mostly sand with some silt or clay. The addition of "black dirt" should be evaluated since it often consists of mainly silt and clay soils, and compacts easily. All amendments should be tilled into soil, rather than just spread on top. (Seeding and Sodding Home Lawns, MES FS-5775-A, Rev. 1995.)

       

  14. How can I get rid of weeds without using chemicals
      See Question 3 for cultural practices. Pulling weeds by hand can be effective in small areas. Be sure to get all the roots. (Weed Control in Lawns and Other Turf, FS-1137-A, Rev. 1994.)