How to Plant, Grow, and Harvest Lettuce from Seeds

• Plant in full sun. Don't plant it in the same spot twice, or it may succumb to wilt.
• Dig deeply prior to planting. Mix in organic soil amendment and add fertilizer that's recommended for vegetables to the top 6 inches of soil, following package directions.
• Distribute the seed down a wide row, or on a raised bed at a rate of about 3 seeds for every 2 square inches of soil surface.
• Cover the seed very lightly with potting soil (about 1/4 inch), and water by sprinkling lightly (use a misting valve). Continue to keep the seed bed damp by sprinkling daily until the seeds sprout - in three to seven days. Then lengthen the watering times and water more deeply. (If your lettuce seeds don't germinate, your soil may be too salty. Give the soil a long deep soaking to leach out salts. Plant again with fresh seed.)
• Stimulate fast growth with plenty of water and fertilizer.
• Protect the plants from slugs.
• Thin seedlings according to package directions.
• If you'd like to grow lettuce but don't have space, plant it in pots or half-barrels filled with potting soil. Feed every two weeks with liquid fertilizer recommended for vegetables.
• Harvest whole heads of lettuce. Leave the roots in the ground, feed and water them, and they will grow new heads. You may lengthen your harvest by taking off only the outside leaves as needed.

The giant whitefly arrived in the San Diego area in 1992. Coming from Mexico, it originally preferred tropical plants. It is now also found in Arizona, Florida, Hawaii, Louisiana, and Texas, as well as other parts of Southern California (and it is spreading northward). Whiteflies are related to aphids, scale insects, and mealybugs, all of which feed by sucking sap from plants.

Once giant whitefly is established it has a stage in its life cycle that shows as white fuzzy filaments hanging from the backs of the leaves. (Many gardeners think this is a fungus and spray with a fungicide, which has no effect.) Once that fuzz shows up, the giant whitefly is much harder to control - that's where learning to recognize the beginning stages of a problem comes in. This is called "monitoring."

A secondary problem with giant whitefly is that, as with many insects, it leaves behind a sticky residue that causes a sooty mold to grow on the tops of leaves. The mold can block sunlight, interfering with photosynthesis, which further stresses the plant. Insecticidal soap is a good product for this purpose.

Also, whiteflies are attracted to the color yellow. The placing of a yellow card covered with a sticky substance near the problem area attracts the whiteflies, which stick to the card. This can also help control them. If the infestation is small, remove any infested leaves, bag them up, and dispose of them (bag securely, or they will migrate to other plants).

Many people are now dealing with this recently-introduced exotic pest. It has branched out to include many new host plants - which shows just how adaptable some pests can be. The Department of Agriculture did side-by-side test studies and has found that "syringing" (washing off, with a strong stream of water) offers the best control. One can also remove them with a small hand-held vacuum, early in the morning, while they are sluggish. This works best on adults, before they have laid too many eggs. While the latter method is effective, it is too labor-intensive for anything but a small garden.

Many insects give 'clues' to help in their identification. Giant whitefly can be recognized in its early stages by examining the backs of the leaves of plants for a white swirl pattern. That's the beginning stages where "syringing" is most effective.

The use of beneficial insects has shown much promise (but we have to be patient). Once a pest is discovered, research has to be done, and it can prove to be quite a challenging task for entomologists. In the case of the giant whitefly, parasitic wasps that prey on the pest have been released by scientists in the various states where the giant whitefly has been found. Until the wasp becomes well-established, gardeners will have to use other methods for control.

Using beneficials and natural means of control for pests is becoming more commonplace. You may have heard the term I.P.M. lately, meaning Integrated Pest Management. The Integrated Pest Management approach uses the least toxic means first for a pest problem. With IPM we are looking for control, not total eradication.

The most important part of this concept is to know what you are dealing with - that is, identifying the pest involved. Many beneficial insects out there aren't recognized as such. In fact, most of the insects in our gardens are the good guys!

Spraying with insecticides every time a bug shows up often compounds the problem. The pests are usually more resistant and the populations increase! In addition, keep in mind that attracting birds to your garden is another way to keep things in balance. For instance, hummingbirds love aphids!

There are many more natural alternatives for pest problems, and with some chemicals being taken off the market (many are showing up in ground water, etc.) it's important to know what you can do to enjoy your garden more. Products like insecticidal soap, narrow-range oils, neem oil, and pyrethrins are more environmentally friendly.

If an infestation becomes bad enough that chemicals are necessary, consult a professional as to which chemical is most effective for your particular situation .