Lawns: Lawns should be fertilized at least once every year with nitrogen-containing products to maintain turf density, the ability to shade out weed seedlings and prevent runoff. If you only do it once, now, around Labor Day as an autumn fertilizer application is the most important. Apply no more than one pound of actual nitrogen per 1,000 square feet per application. Autumn fertilization in early September promotes faster green-up and growth next spring. You can use organic lawn fertilizer products versus conventional ones, but they contain less soluble nitrogen and grass won’t green up as fast. Also, soil micro-organisms must break down organic products to release the nitrogen, unlike conventional soluble products. You will also need to apply more often during the season to get the same results as conventional products. A benefit to organic products is that after roughly 10 to 20 years of use, organic nitrogen accumulates in the soil, so grass begins to need less fertilization.

Visit http://learningstore.uwex.edu/ and type “A3958” into the search box to view a publication on organic lawn care titled Organic and Reduced Risk Lawn Care. It has suggestions for organic and reduced risk products for lawn fertilization and tips on how often to apply them.

For conventional lawn fertilizers, select one with at least 25% to 50% slow release (insoluble) nitrogen — this information is on the bag. Avoid blends with high rates of quick-release (soluble) nitrogen that will not stay in the soil long, especially in areas with sandy soils or high water tables to avoid getting the product in groundwater. Grass grown in sun needs one pound of nitrogen per 1,000 square feet; turf in shade needs one-half pound of nitrogen per 1,000 square feet, because it isn’t growing as vigorously. Don’t add more in shade thinking it will get you stronger turf, because it will just result in weak lush growth that may be more susceptible to diseases like powdery mildew.

You can reduce the amount of fertilizer you need to apply annually by up to one application per year by leaving clippings on your lawn. Visit http://learningstore.uwex.edu/ and type “A2303” into the search box to view a publication titled “Lawn Fertilization” with more information on lawn fertilizers and search for “A2306” for a publication titled “Calibrating and Using Lawn Fertilizer and Lime Spreaders.”

Vegetables: Late blight of both potato and tomato has been identified in various counties in Wisconsin this year. Late blight is a fast-spreading fungal disease of tomato and potato that can kill entire plants in 7-10 days. Symptoms on the leaves of tomato or potato plants start as pale green or olive-green areas that quickly enlarge to become brown-black, water-soaked, with an oily appearance and progress to developing a whitish-gray fuzz as spores develop. Stems may show dark-brown to black areas that eventually also become covered with whitish fuzz.

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Tomato fruits with late blight infections develop large, often sunken, golden- to chocolate-brown, firm spots with distinct rings. Potato tubers develop a different symptom, with reddish brown discoloration under the skin that may become sunken. Do NOT compost any plants infected with late blight — dispose of them in a plastic bag in the trash.

It is important if you suspect late blight to have the disease confirmed — call your local County UW-Extension office for more information. You may also check out the following fact sheet that has further recommendations at https://pddc.wisc.edu/. Look under the fact sheets tab and scroll down to the title “Late Blight.”

If you do have late blight, be sure to practice good garden sanitation, cleaning up plant debris and disinfecting tools, tomato clips and trellises. Next year, consider using a resistant variety of tomato. Some resistant varieties include: “Better Boy,” “Golden Sweet,” “Green Zebra,” “Juliet,” “Legend,” “Magic Mountain,” “Matt’s Wild Cherry,” “Pruden’s Purple,” “Regal Plum,” “Roma,” “Slava,” “Stupice,” “Sun Sugar,” “Wapsipinicon,” and “Wisconsin 55.”

Depending on the variant of late blight that is present in a particular growing season, some tomato varieties may perform better than others, but “Magic Mountain” and “Regal Plum” have shown excellent resistance to many variants of the late blight pathogen.

Lisa Johnson, Dane County UW-Extension horticulture educator