Forsythia Are In Bloom; Time To Fertilize Your Lawn
By Mark Saidnawey, WBZ Gardening Expert and Owner of Pemberton Farms in Cambridge, Ma
Aired: April 19, 2011 10:50 AM
What Does A Pre-Emergent Control Do?
Pre-emergent herbicides are chemicals that prevent the germination of weeds in your lawn. These herbicides control annual grass weeds like crab grass, chickweed and dandelions by inhibiting their cell division in the young root system. The failure of the root system to develop, results in the death of the young seedling weeds shortly after germination.
When Do I Apply Them?
Timing is very important. Pre-emergent controls must be applied before the bad “weedy” seeds are allowed to germinate. For us, here in New England, it is generally the middle of April- especially when you see those brilliant yellow flowers of the forsythia in bloom. That is my signal.
So Which Type of Fertilizer Should I Use?
Synthetic vs Organic…
We are all familiar with those television commercials for Scott’s lawn fertilizer with crabgrass control. This a great choice for a synthetic lawn fertilizer and is very effective the same year it is applied. However, with the increasing desire to use only organic products in your lawn and garden, there is now a great alternative for you to consider.
Gaining in Popularity over the past few years, corn gluten meal (CGM) is a natural substitute for synthetic pre-emergent herbicides. The use of corn gluten meal as an herbicide was actually discovered by mistake during a turfgrass disease research project conducted at Iowa State University. Since then, CGM has been proven to prevent weeds from sprouting including seeds from many weeds such as crabgrass, chickweed, and even dandelions. You should apply CGM the same time you would any other pre-emergent, then a second time around mid-August. Spread the product evenly, at a rate of twenty pounds per 1,000 square feet of lawn. Water it lightly into the soil to activate it. The CGM should remain effective for five to six weeks each time you apply it.
- Whichever type of pre-emergent crabgrass fertilizers you choose, you should apply it evenly over the entire lawn. Even if you have only noticed crabgrass in certain areas of the yard in previous years, take the time to cover the entire lawn. Spots that are skipped can allow stray crabgrass seeds to germinate, grow and spread.
- Do not aerate your lawn after application and wait three months before reseeding any part of the lawn
- If you are planning to over-seed on bare spots, or perhaps reseed the entire lawn, you will need to wait up to 3 months before applying new seeds as the pre-emergent will prevent any germination of new grasses.
Best of Luck.
WBZ Gardening Expert and Owner of Pemberton Farms