Wait and watch before you fertilize

As I did last week with lawns, I am again going to suggest that despite the onslaught of brainwashing TV ads, I have come to believe that now is not the time to feed your perennials with fertilizer. You surely want to feed the soil they are in, however, and if you have been following the book, you know that is not the same thing.

Let's start with the chemical fertilizers you are being bombarded with encouragement to apply every spring, perennials included. It is true when plants get fertilized, they usually grow faster and bigger. However, this is not always a good thing. Fertilize at the wrong time and plants become weaker as a result and more susceptible to attacks by insects and diseases.

"Come, Jeff," you are saying. "You can carry this anti-chemical stuff just so far."

OK, but consider that your perennials have been dormant all winter, just waiting to grow. With or without fertilizer, they will break dormancy and grow. That is what they do in the wild, where they originally came from. In fact, they will develop into pretty nice plants without you doing anything at all. That is why you planted perennials in the first instance, wasn't it?

The point is, you don't ever need to feed perennials chemicals -- but especially not now. Let them come up and see how they are doing. Don't be a knee-jerk fertilizer. If they are planted in soil with good structure (meaning it will allow water to drain), they will grow this time of year with just the addition of water.

How about organic fertilizers? These you don't feed to plants, but rather the organisms that will. Even so, why apply them now? Let your perennials produce the substances that attract the life that will feed them to their roots. Apply organic foods and you compete with the plant. Again, wait until the plants are up and running before you decide if they need help. If you have been mulching properly and using organic rather than chemical foods, they should do fine.

The primary exception to this rule, of course, is if you know your plants are not doing well from last year. In such case, make sure your organic food is placed down in the root zone. Poke holes and push the stuff down. Surface applications will take much longer to produce results.

The other exception is compost tea. This is a great time to apply some as the critters in it will cycle the nutrients in the soil and feed the plants if they need it.

If you really want to do something else great for your perennials, apply a quarter to one inch of compost (you can't put down too much) around them. This will not only ultimately provide food and cover for some of those soil critters you want, but it will also add some to the population as well. You don't need much. A teaspoon of soil has billions of bacteria and several feet of useful fungal strands.

Similarly, a good carbon-filled mulch layer provides food for members of the soil food web throughout the year. Leaves and bark chips are the best for perennials. Apply a two-inch layer throughout beds to smother weeds, as well. Partially composted leaves count as mulch.

Speaking of leaves, this is a great time to mulch perennials (and around trees and shrubs). But did you save leaves to do so? Fortunately, some folks (nonreaders, obviously), foolishly clean up what is left from last year's leaf fall, bag them and leave them on the curb to be taken to the landfill. If you need some, all you have to do (and you definitely should), is drive around and pick up some the night before collection. One bag should do a 10-by-12 foot perennial bed. It will take two bags or so to cover the area under the drip line of a normal size birch. Remember my warning when retrieving leaves and yard debris from other's: Avoid homes with dogs.

So, hold off on feeding not only the lawn, but perennials as well. A bit of compost tea for the soil, mulch and compost. But forget the knee-jerk spring feeding.

Jeff Lowenfels is America's longest running garden columnist and author of "Teaming With Microbes: The Organic Gardener's Guide to the Soil Food Web." He can be reached at jeff@gardener.com.