Documents: Gardening From: Gardening From Alaska:

Gardening from Alaska

...Fertilizers
by Jeff Lowenfels
by Jeff Lowenfels

email: jeff@gardener.com

Jeff is the Past President of the Garden Writers of America, a columnist with the Anchorage Daily News, Host Alaska Gardens and Supporter of Plant a Row.


May 27, 2007

If you re out getting nursery supplies this weekend, you will see piles of fertilizer and lime stacked up for sale. Scientific Gardening advocates you cut back on these. The “nitrogen-is-nitrogen-whether-it-comes from-a-plant-or-man-made-chemicals” argument used to work, but it doesn’t hold up under the microscope. Literally.

I, of all people, will be the first to admit high nitrogen lawn fertilizer greens-up your lawn. Sure it works and it works well, but it is like heroin: after the first few applications, the lawn can’t stay green without a fix.

The same can be said for all of the well-advertised fertilizers for vegetables, flowers and containers. They work and they work well. because they flood high concentrations of nutrients past a plant’s roots where some are absorbed. On the down side, only a little is also absorbed into the soil and most of it ends up in local water bodies and streams.

In addition these fertilizers are chemical salts. They kill the soil fungi and bacteria, protozoa, nematodes, mites and other soil life by sucking the liquid from their cells. Worms and the bigger bugs avoid areas fertilized with synthetics. Pretty soon, there isn’t enough life to sustain a healthy foodweb.

Of course, initially your plants do fine. They are being feed. Unfortunately, however, this is like living off soda and candy. You can survive, but something eventually gives.

What gives here is in your soil. The good fungi and bacteria disappear, both those mycorrhizal fungi that play such an important part in feeding plants and the soil bacteria at the base of the food chain. Organic matter stops decaying and plants start getting mildews and molds and the zucchini doesn’t taste very good. Delphinium defoliating caterpillars appear and the gooseberries drop leaves because of fly larvae.(both relatively new phenomenon here in Anchorage).Hmmm, lilacs with mold, strawberries with blight, more dandelions than ever, foxtail invasions and where are these thistle plants coming from?

You chalk it off to the short, cold, wet, Alaskan growing season. However, I am telling you it is the lack of soil life caused by the fertilizers, fungicides and pesticides you apply.

So, we are forced to resort to carpet bombing with fungicides, pesticides and more fertilizers to keep our plants healthy and green, but science has now shown the reason we have to do this is because the natural protections afforded by the soil good guys are gone. No good guys to form root protecting barriers, necessary hormones and antibiotics, the right proteins or stretching the reach of the roots to get needed micro-nutrients. And, there is no competition for the bad guys, nothing to eat them or their food.

You can continue to get along just fine with high nitrogen fertilizer and the eventual fungicides, pesticides and more fertilizers you will need or you can bring your yard, and that is what it is folks, a yard, not some industrial chemical repository, back into balance.

So what am I recommending?

First, it doesn’t matter what you use to feed your basket and container plants unless you grow food. These last only one year so go ahead and use your favorite commercial fertilizer or switch to good compost, compost teas or a generous amount of fresh, local topsoil. When you plant them, forget the vitamin B1 and instead, add mycorrhizal supplements.

Next, as for gardens and container grown vegetables, use compost, mulch or a few inches of fresh local topsoil without additives except for mycorrhizal fungi. The best way to restore the soil foodweb, however, is to drench gardens with good compost tea.

If you still want to use “commercial” fertilizers, at least cut back on how much with a goal of applying no more than 2/10 a pound of nitrogen per year for every 100 square feet. I know the math is daunting. It is really only the first number you care about. If the nursery can’t help you with the math, remember you need just a over 2 pounds or 8-32-16, exactly 2 pounds of 10-10-10 and about 1 and 1/ 2 pounds of 16-16-16 per year.

Or use organic fertilizers. Most are sold in powder form and work with existing spreaders. The best for lawns as well as gardens is soybean meal (7-2-2) or cottonseed meal available at mill and feed stores as well as some nurseries. Three pounds of soybean meal or cottonseed meal per 100 square feet does it for flowers, vegetables and shrubs as well as lawns. Fishmeal works well, too, though it has a slight odor for a short period of time.

If your favorite nursery or outlet doesn’t carry these low number fertilizers or mycorrhizal products, demand them. Ask for them ‘MIKE-OR-EYES-AL” until your favorite stores start carrying them. They are very important to Scientific Gardening and will definitely make your gardens better. I have sources if they are looking for them. Science is on your side. Let them know you are interested.

Finally, as for those lawns, the only thing you should be doing right now is watering them. This will first get the grass growing and then you can decide what, if anything, it needs. Once you get the soil foodweb back into balance by restoring soil life, you won’t have to worry about adjusting its pH. So for this season, at least, forget lime. Work on restoring the soil life, which, incidentally, most lime kills. By adding compost, compost teas, mulch and local topsoil, the pH will naturally readjust to proper levels. But again, this weekend, simply water.
 

  • New Eden
  • Kids Garden
  • Plant a Row Grow a Row