Lettuce can be grown by the home gardener fairly easy, if you keep a few important points in mind. Lettuce is best grown in the spring and fall. It does not tolerate summer heat without some protective measures. And it will not survive winter frost.
Lettuce is also very attractive to slugs and snails which we will discuss below.
First, prepare your soil. Add well aged manure to the soil to provide nitrogen for healthy growth. Add manure as soon as you can work the soil in the spring (at least two weeks prior to planting the lettuce).
Plant seeds in full sun 1/8 inch deep in rows, 6 inches apart. If you plant new seed every two weeks you can have lettuce all summer...depending on having moderate temperatures.
For mid-summer yield you must protect the lettuce from summer heat. As the weather warms, begin planting in partial shade, somewhere where the afternoon sun will be blocked by the house, garage or a tree. If you have taller plants nearby, such as corn, sunflower, etc., put the lettuce in the shade of those plants.
Watering And Fertilizing
Lettuce does not have deep roots, they only go a few inches under the soil surface. Therefore you do not need to water deep. Soak the top 3 inches of soil about twice a week and your lettuce will be happy. Of course if you live in a location with exceptional rain or heat (a lot or too little) you will need to adjust your watering schedule. Avoid getting the leaves wet when you water. This invites disease.
Fertilize the lettuce when the seedlings are about 3 inches tall with a 5-5-5 or 10-10-10 fertilizer (the numbers represent the amount of nitrogen, phosphate and potassium that are contained in that particular fertilizer respectively).
If using a water soluble fertilizer just follow the instructions on the label to spray the lettuce. If using a dry fertilizer scatter a tablespoon of fertilizer around the base of the plant, without actually touching the plant, then scratch it into the top inch or two of soil.
Lettuce does not compete well with weeds or pests. Keep the weeds pulled and hand pick pests off the leaves. I would not use poisonous insecticides on my lettuce. If you must spray, use insecticidal soap or an organic (non-poisonous) pesticide.
The biggest enemy of lettuce in the garden is slugs and snails. They can practically destroy lettuce in about two nights. The best method to eliminate slugs is to go out in the garden every morning at sunrise and hand pick them. Look in damp, shady areas and you will find them easily. Do this until you can not find any more.
You can also help eliminate slugs by removing any article in or near your garden that provides a home for them. Slugs love to hide under old grass clippings, wood, cardboard or anything else that gives protection from the sun. So, clear your garden of all of these items.
PLEASE DO NOT USE COMMERCIAL SNAIL BAIT
You can buy snail/slug baits at your garden shop or home improvement store. These products are effective, however we strongly discourage using any of these baits except under specific conditions. These baits are poisonous and can cause sickness or death to animals, small children and wild life (dogs are attracted to it).
You may have seen some slug bait advertised as "Pet Safe". Recent studies have reported dog poisoning caused by these so-called pet safe products. The ingredients list on these products list Iron Phosphate and "Inert Ingredients". Iron Phosphate occurs naturally in nature and is harmless to dogs, children, wild life and you. It also does not kill slugs!
The problem is that the "Inert Ingredients" contains EDTA, a substance that, when combined with Iron Phosphate, makes the mix deadly. Why is it not identified on the lable? Because no regulatory agency requires inert ingredients to be identified.
Think of it this way. If these products were completely safe, they would not harm people, animals, worms...OR SLUGS!!!
Do some research on the web (Google "snail bait and EDTA") then make up your own mind. We strongly advise against using snail bait. But if you choose to, only use in an area that is completely isolated from pets and children (a locked greenhouse or fenced garden). Personally, I would not put any substance in my garden that will kill animals, especially on vegetables I intend to eat.
For more detail on eliminating snails and slugs read our article HOW TO GET RID OF SLUGS