Q. The pepper plants in my garden have been losing their leaves, starting at the bottom. They turn yellowish and fall. Most plants have lost the majority of their leaves now.

I have a large garden that I have to water by hand and was wondering if they might not be getting enough water . Or maybe too much? Or could something else cause this?

A. Pepper plants lose their leaves for a variety of reasons. Plants do respond to drought conditions by dropping their older leaves first, in this case, the lowest leaves. If you have not been able to provide that magical inch of water weekly during the growing season, drought stress could be a factor. This could be coupled with heat stress, given our hot, dry and sunny weather.

Overwatering can also cause leaves to yellow and drop. Gardeners can kill their plants with kindness during hot, dry weather by watering too much, too frequently. Many plants look a little wilted during the heat of the day: They curl their leaves slightly to minimize moisture loss through transpiration during very hot weather. But they recover when the sun sets. Watering deeply once or twice a week once the plants are established should be sufficient, even when it is hot and dry. Apply the water to soil as much as possible, rather then dousing the plant. This puts it at the root system where it is needed and keeps the foliage dry to reduce the incidence of disease problems.

Because you have to hand water a large garden, I hope you use mulch to help conserve soil moisture and moderate soil temperatures during the growing season. Organic mulches such as straw or shredded leaves can do a better job than plastic mulch during such hot, dry weather unless you have drip irrigation installed under the plastic.

If you apply high nitrogen fertilizers -- especially during hot weather when the plants are under drought stress -- you can burn them, which will also cause leaf drop. Organic or inorganic fertilizer placed directly into the hole at planting time can have the same effect on transplants.

Although you do not mention any kind of spots on the leaves or fruits, peppers are susceptible to a number of diseases that can cause the leaves to yellow and drop prematurely. These include cercospora leaf spot, a fungal disease whose symptoms include round or oblong spots on the leaves and stems. These spots often have light gray centers with dark brown borders.

The fungus is carried on infected seed and may survive over winter in the garden on infected plant material. Long periods of warm, wet weather are ideal for this disease to develop.

Control options include thoroughly cleaning out the garden at the end of the season and not saving seed from infected plants. Dispose of infected plant plants in the trash or by burning them rather than tossing them on the compost pile. Purchase fresh seed or disease-free transplants for next season's garden, and do not plant them where infected plants were grown this year for at least two years.

Avoid overhead irrigation and do not work in the garden while plants are wet from rainfall. Spray plants with basic copper sulfate at the first sign of disease, making repeated applications. Follow label directions regarding intervals between applications.

Bacterial spot is a bacterial disease characterized by leaf and fruit spots. Spots start as irregularly shaped water-soaked spots on the undersides of the leaves. They become purplish with black centers, and you may notice a yellow halo around the spot. On fruits, the spots start as water-soaked areas that turn brown and become raised. They have a corky feeling.

The disease can survive over winter on infected plant debris and is transmitted from plant to plant by splashing water or by hands or tools that have been used on infected plants. Spray basic copper sulfate at the first sign of the disease, and use the same cultural controls mentioned above. Try not to plant pepper and tomato plants in the same place more than once every three or four years because they are in the same family and susceptible to many of the same maladies.