In last month’s issue, we ran a story entitled, “The Grass Is Always Greener,” (April 2011, p.9 or online at http://www.vermontmaturity.com/?cat=8)
A reader suggested we get some clarification on some of the suggestions in the article, such as how much fertilizer should be used — environmentally speaking — so we contacted the Vermont Department of Agriculture. Matthew Wood, the Pesticide Certification & Training Coordinator, responded with the following suggestions:
The 10 steps outlined in the article included some rather expensive ones, such as renting a core aerator as well as no less than four fertilizer or pesticide applications.
At the beginning, the article suggests applying a weed killer. I would only suggest that if you do indeed have a weed problem, and only after you have improved the turf health through the fertility and mowing practices discussed below.
Mowing to 1” is far too short, and recommendations for turf mowing height are anywhere from 3 to 4 inches in height now. That will promote deeper roots that will give the grass plant access to more water and nutrients, making it more drought-tolerant and helping it to out-compete the weeds by shading them.
The aeration is a good idea, as well as following with compost applications to fill in the holes. This is a good cure for compacted soils that get lots of traffic.
The starter fertilizer recommended in the article will most likely have more phosphorous in it than what the lawn needs, and this is what the current legislation is trying to address. We don’t want people applying phosphorous to their lawns without first getting a soil test that shows it is needed, otherwise it just tends to run off, polluting fresh water and possibly causing algae blooms.
Watering well initially is important, but daily watering of only ¼” won’t be enough to promote deep roots. Frequent light watering is not good for turf as it encourages shallow roots. It is better to do less frequent, deep watering to encourage deep roots for the reasons mentioned above. Water as needed, so obviously it won’t be needed if it rains more than 1” in one day.
Again, the fertilizer recommendations at the end seem a bit excessive, but if those are done, they should be with a phosphorous-free fertilizer. The middle number on the fertilizer bag is the phosphorous, so people should look for the zero in the middle (5-0-3 for example). Also, only apply the crab grass or grub control pesticides as needed. If you don’t have crab grass or grubs, then save the money and don’t use them.
I would encourage anyone that wants to improve their lawn but does not know exactly what the problem with it is to ask a professional for help. UVM Extension is a good resource for identifying pests, diseases, and weeds.
Here is a link to the lawn-to-lake website with great recommendations for maintaining a healthy lawn without polluting water with unnecessary pesticides or phosphorous: http://www.lawntolake.org/tips.htm