GARDENER'S READING ROOM
Lawn Care

Spring Lawn Care

This is the time of year when we all start to think about our lawns. In the nursery the questions begin: "Have you ever seen so much moss?" "I must have cranefly in my lawn. What do I need?" "Why is my grass so yellow?"

Hopefully, we were all good about getting our fall fertilizing done (Labor Day and Thanksgiving), because that benefits the spring and summer lawn more than almost any other thing we can do. However, there are still some great things to do this season to have a healthy lawn this year.

The first thing we should all do is take a look at our lawns. Are weeds or moss a problem? How thick is the grass? How well does the lawn take water? This last question is very important. Many lawn problems that we think are diseases are really watering problems. If it's difficult to see what's going on, bring a sample of turf (about 12" by 12" with the roots attached) into Sky and let one of our experts look at it for you. We can help diagnose what's happening.

Take a look at the fertilizing schedule. A healthy lawn requires a consistent source of nitrogen. Feeding 3-4 times a year with a good organic fertilizer such as Dr. Earth lawn food takes care of this. Look for an N-P-K ratio of about 3-1-2 and avoid high nitrogen numbers. Big swings in nitrogen loads (such as you get by not fertilizing for a while and then applied a high-nitrogen fast-release fertilizer for quick results) can lead to fungal problems and thatch buildup. A good schedule for fertilizing is Valentine's Day, Memorial Day, Labor Day, and Thanksgiving. If you want to skip one, skip Memorial Day (once you have been on a good program for at least a year).

Next, take a look at moss, thatch, and overall thickness. Moss is fairly obvious. To see thatch, lift up a section of turf and look at the area between the soil and the grass blades. The cross section that looks like a sponge is thatch. If it is 1⁄2" thick or more thick then it could cause problems, especially with water penetration. If thatch is a problem, either a hand thatching rake (available at Sky) or a power thatcher (which can be rented from Aurora Rents) is a short term solution. (The long term solution is usually to alter your fertilizing program.)

If moss is the problem, we can get rid of it fairly quickly by applying iron (ferrous sulfate) to kill it, then raking out the dead moss with the thatching rake or power thatcher.

After getting rid of thatch and/or moss, the next step would be overseeding to thicken up the turf. If we've applied iron sulfate moss control, we need to wait 3-4 weeks before overseeding. In any case, night time temperatures should be in the mid to upper 40's for the best success (which is usually not until April). Sky has a variety of seed blends to match varying conditions.

Finally, and maybe most importantly, are our lawns getting the proper amount of water? One of the biggest myths of our area is that it rains a lot in Seattle. The truth is that it rains frequently fall through spring, but not in large quantities and certainly not often or in amounts necessary for irrigation the rest of the year. Our lawns need infrequent, deep watering for best health. During the summer months, lawns need about 1" of water a week - and it's better if they get it all at once rather than a little at a time. In lawns that don't absorb water well, aeration can help. In some cases a surfactant like EZ-Wet or Perc-o-late is useful.

Remember, good lawns need consistent fertilization, thick turf, and deep watering. These simple concepts help us all to have a nice green lawn year round.

By Charlie Shull, WCN
Skylights Spring 2009, Vol 24, No. 1

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