High-nitrogen fertilizer, strawberries don't mix

This is probably the same fungus that attacks the fruit of strawberries, leaves and fruits of tomatoes, cucumbers and squashes. In fact, it attacks about 100 different kinds of plants. It is known as botrytis and sometimes the word "rot" is added to it. Many know it as "gray mold." In addition to killing off leaves, it can cause seedling damp-off and fungified fruits. An infected strawberry will turn black and be coated with a fuzzy gray mold. Essentially, it causes cells of the plant and its fruit to collapse.

High humidity, still air and moderate to high temperatures almost always cause botrytis. It's fun to walk into a steam bath greenhouse, but most of the plants we grow in them would do better with moderate humidity and much better air circulation. A fan always helps.

On those ivy pelargonium hanging baskets and when early attacks hit tomatoes, cucumbers, squash and berries, make sure to immediately remove dead leaves and discard them far from the garden or greenhouse. You can spray a fungicide on your plants, but read labels very carefully and consider if it is too late.

Next, there are reports of hordes of aphids inundating meadow rue stems and flower buds. Seeing these infestations is a testament to the breeding abilities of these critters. Thousands can cover up the buds and the top inch or two of stem. They suck the sap of the plant and produce honeydew that feeds fungi, which fruit and end up coating the aphid colony and the flower buds white.

You can keep some of these aphid populations in check simply by knocking the stem a few times. Spray them with cold water. You can try AzaMax. Some swear by a homemade garlic spray (crunch a few garlic cloves in a quart of water). Many run their fingers over them and squish 'em.

Strawberries with big leaves and very, very few fruit are suddenly a complaint this year. The cause is almost always too much nitrogen. Sometimes this comes from the gardener and sometimes the hit occurs at the nursery before the plants are sold. Compost, kelp and a bit of soybean meal are all you need. High-nitrogen fertilizer is not what you need. Many strawberries are dependent on the length of the day. Overfed plants may not flower this year. Simply put, in all things yardening, lay off the high- nitrogen fertilizer.

OK, a few folks with greenhouses are asking why their tomato flowers are rotting rather than forming tomatoes? There are three causes: lack of water, failure in pollination or, most likely, calcium deficiency. Once again, high-nitrogen fertilizers -- represented by the first of three numbers on all fertilizer labels -- negatively impact the availability of calcium in soil. You can add calcium to fix the balance.

Similarly, if the veins of your plants are purple and the leaf is getting there too, you need to find a way to give your plant phosphorus. This is the second number in the trilogy on the fertilizer package. This doesn't mean go out and get a high-phosphorus chemical fertilizer. Get something that just has phosphorus but is still below 10 on the label (like 0-10-10).

It is not too late to stake delphiniums. In fact, you had better get to it. The stems are hollow and will snap with wind and the weight of water from a good rain or hard watering. Malva and other tall plants could use some support, as well. It is not too late for peonies, many of which are about to burst into bloom.

If you have been following my advice and doing nothing more than making sure that your lawn has been getting enough water, it is now time to evaluate your lawn and consider its needs. It should be a nice green, not the dark green of a force-fed lawn but a clean, healthy color. If not, why not?

First, the lawn might need aeration. Can you push a dowel into the soil easily? Does it feel like hardpan? Is it hard to dig into? You can rent an aerator and do the job in a couple of hours. Pull plugs and leave them to decay. Then add soybean meal or other organic lawn food and endo mycorrhizal fungi in the form of "Endo."

Next, it might need organic matter. No amount of feeding will help a lawn that needs organic matter. Sand base soils need supplementing. Yes, clippings, and that includes leaves in the fall, add organic matter. However, you may need to bring in a half-inch or so of compost to cover the lawn. Dump piles around the lawn and then rake them in.

Finally, your lawn really may need feeding. Organic is the only way to go. Soybean meal is great. Arctic Gro natural is great. Alaska fish-based foods are great but may stink. Go for it. Just make sure you stay organic and use things with numbers under 10-10-10.

Jeff Lowenfels is a member of the Garden Writers Hall of Fame. You can reach him at teamingwithmicrobes.com or by calling 274-5297 during "The Garden Party" radio show from 10 a.m. to noon Saturdays on KBYR AM-700.