What you need to know about fertilizers

Over the past two weeks the weather quickly turned from cold and wet, to very hot and dry, punctuated by some nasty thunderstorms throughout the region. Soil moisture levels, which prohibited tillage for many gardeners the past few weeks, have dropped to optimal levels for planting.

I finally got most of my garden planted last weekend when the soil temperature in my raised beds reached 60 degrees. I do not rely on the calendar to advise me when to plant, when I can buy a soil thermometer for less than $10 at my local garden center.

Typically by Memorial Day weekend, it is safe to set out any garden transplants, but even though the transplants may survive, they really do not grow properly until their roots can expand. Those of you who rely on strictly organic fertilizers may have an even longer delay before nutrients are available to the plants.

Water-soluble chemical fertilizers such as Miracle Grow, or the equivalents provide instant nutrition for developing plant roots, whereas organic fertilizers such as manure, dried blood or even compost must be broken down by soil microbes before the plants can utilize them. This breakdown process is temperature dependent with little activity when the soil temperature is below 50 degrees.

I use both types of fertilizer in my garden, since the “starter” solution I use gets them off to a good start and the organic fertilizer feeds the soil and the plants for late season nutrition. The difference between organic and chemical fertilizers is that chemical fertilizers provide “instant” nutrition for the plants, since the water soluble forms of nitrogen, phosphorus, and potassium are readily taken up by the plants, whereas organic fertilizers must undergo additional microbial degradation.

Chemical fertilizers are also subject to being washed out of the soil by heavy rain and then they can become serious causes of pollution, especially if they get into bodies of water. Runoff from organic sources of nutrients, such as barnyard manure, can also seriously pollute bodies of water, but in the backyard vegetable garden they add valuable organic matter as well as beneficial microbes.

Chemical lawn fertilizers, in particular, have been identified as a serious cause of water pollution. According to Cornell turf grass specialist, Dr. Frank Rossi, the average homeowner can have a very nice looking lawn without ever having to use chemical fertilizers or any herbicides at all. The key technique to achieving such a lawn is allowing the grass to grow to at least 3.0 to 3.5 inches long, before mowing, but mowing often enough to allow the grass clippings to remain in place without forming windrows that smother the grass beneath!

Grass clippings contribute about one pound of actual “organic” nitrogen fertilizer per 1,000 square feet per season as they decompose. So the message is to mow often, but keep the grass tall by removing about ½ inch at a time. Collecting grass clippings does more harm than good in general. If your mower has such a “bagging” attachment, I suggest you remove it.

If you really want a lusher lawn, the best time to apply any sort of fertilizer is in September, the second best time is right now. Make sure you carefully follow the application directions on whatever lawn fertilizer you decide to use. My friend Lester once misread the directions when fertilizing his lawn, mistaking 100 square feet for 1,000 square feet! The grass was seriously “burned” as a result and took years to recover.

My lawn is about 50 percent grass and 50 percent assorted weeds. One of these “weeds” is wild thyme and if I could have a 100 percent wild thyme lawn, I would be very happy!

This low-growing plant never requires mowing and it smells great when it gets walked on. I also have a ready source of thyme to season my salads!