Common spring lawn questions answered

The Central Missouri Master Gardeners are a volunteer group of 191 members, 122 of whom are Cole County residents, who maintain 11 beautification sites in Cole County, which are nonprofits or public entities. Master Gardeners must complete a basic training program of at least 30 hours of horticultural training, as well as 30 hours of volunteer service. The Missouri Master Gardener program is supported by the University of Missouri Extension.
The Central Missouri Master Gardeners are a volunteer group of 191 members, 122 of whom are Cole County residents, who maintain 11 beautification sites in Cole County, which are nonprofits or public entities. Master Gardeners must complete a basic training program of at least 30 hours of horticultural training, as well as 30 hours of volunteer service. The Missouri Master Gardener program is supported by the University of Missouri Extension.

Q. I forgot to put crabgrass preventer down in March. Am I too late? Also, I put some grass seed down on some bare patches. Do I put the crabgrass preventer over those spots or not?

A. You are not too late; you are right on time. The advised time to apply crabgrass preventer in central Missouri is between April 1-15. I receive several calls each year as we approach spring from individuals wanting to get an early start by putting down crabgrass preventer too early. The active ingredient for crabgrass preventers inhibit the seed germination and emergence of crabgrass, but this active ingredient eventually breaks down. So if putting out too early, then activity is lost too early in the summer season (i.e., June).

Crabgrass is a warm-season grass that can germinate well into the summer (it does not survive through our winters). Rainfall also advances the breakdown of these preventers. Thus, in 2015, many folks noticed crabgrass growing as the summer progressed, due to our rainy May and June. The only "fix" in this situation, is to apply crabgrass preventer in late May or early June. Another effective way to suppress crabgrass is to mow high and maintain a thick cover of grass, for seed will more readily germinate where the soil is bare.

If you have seeded any grass this spring, you need to avoid putting these preventers on those areas. For they will prevent any small seeds from germinating or emerging. You can apply them about three weeks after you see the grass has started coming up.

Q. I have moss growing in spots in the lawn. I rake it up, and it grows back. Is there anything I can put down to kill or prevent it?

A. There are some products, but we first advise you fix the underlying problem. Moss generally prospers where you have acid soil, shade and compaction, so first is to take a soil test. It will likely advise you to apply some lime, and this will help some. Secondly, if the shade is heavy, you can try pruning some lower branches on the trees. Also, avoid trying to grow the grass right up to the base of the tree. Create a mulched area around the tree base, anywhere from a couple of feet away to up to 10. Or plant a ground cover of some kind. If you suspect compaction, then you can rent a machine to improve water infiltration. It is called a core aerifier, and it takes little plugs of soil and pulls them out and drops on the top of the ground. If you do this annually for a compacted area, it will help greatly, and you should see marked improvement immediately and substantially looser soil after several years. If the moss is very bad, you can purchase commercial "moss killer" to assist with its control while you correct any underlining problems.

Q. I'm trying to have my landscaping be organic and wanted to know what would be a good nitrogen source for spring lawn fertilization?

A. For lawns, there are three products often used: compost, corn gluten and organic lawn fertilizers (such as Milorganite). Regarding the latter, it is a well-known product and is similar to compost but produced from sewage in Milwaukee, Wisconsin. It is dried so it spreads relatively easily and will give rates for its use. It does have a bit of smell; applying just before a rain will help, as once it gets a nice rain on it the smell diminishes. Don't apply it just before an outdoor party.

Compost can also be used but may be more difficult to spread, as many are somewhat moist, if not even a bit wet. Also, the amount of compost to apply is sometimes difficult to know, as many sources of compost do not provide a fertility guarantee (the numbers on synthetic fertilizer containers for N-P-K). One of the few sold locally that provides this is Earlybird Compost and this product is generally on the dry side, so spreads a bit easier. As with the Milorganite, it has a bit of a smell, so see those application suggestions to minimize. For lawn fertilization, we advise 1 pound of nitrogen per thousand square feet of lawn. Earlybird compost is two percent nitrogen, so a 50-pound bag should be used for 1,000 square feet.

Lastly, corn gluten can be purchased and is formed into easy-to-spread pellets. It is about nine or 10 percent nitrogen, so 10 pounds per 1,000 square feet. This is five times less "weight" to spread and easier, too, with no or only minimal odor. Corn gluten also has a beneficial trait that while decomposing it prevents weed seeds from germinating, acting a bit like a crabgrass preventer. MU Extension has a helpful publication on this topic called "Natural Lawn Care."