How to grow lettuce in a biological way
We often do not know what we find in the vegetables we buy and above all we do not know if we ingest pesticides or dangerous nitrates. This is one of the reasons for making this little guide on the cultivation of lettuce (Lactuca sativa L.), even for those who produce them to market them.
To start well, pay attention to the cultivation land; the optimum is a soil with a pH of between 6.0 and 6.8, well drained and rich in organic substance (better mature cow dung) and the minimum sowing temperature of at least 2 ° C (so it can be started in a sheltered place with transplants when the weather permits). The sowing should be carried out at 5-20 mm of depth, covering with a thickness of soil mixed with organic substance of 1-1,5 cm to which you can add a few centimeters of organic compost and mulch (this is to avoid growing weeds and keeping wet the soil). Never use chemical fertilizers; especially nitrates.
In case of planting of different varieties, space these at least 5 meters to reduce cross-pollination. The distance between the seedlings instead must be at least 10 cm, for those with leaves and at least 25 cm (depends on the type of lettuce) for those on the head. After the germination of young seedlings, the thinning is done, leaving the most vigorous ones and tearing the others out. Irrigation must be constant.
For the harvest, consider that for the sheared ones, the leaves should be harvested when they have reached about 15 cm, while for those in the head you will have to cut the head 2 – 3 cm from the ground so that in its place it forms a new .
The cultural cycle of lettuces can last up to 90 days after sowing.
For a good organic production method we must then take care of some important rules; as lettuces attract rabbits, snails, aphids and cabbage worms; it is good to use some measures. To keep rabbits away, mix 2 tablespoons (30 g) of cayenne pepper, the same amount of garlic powder, 1 teaspoon of liquid detergent and 600 ml of hot water; stir the mixture and leave it to stand outdoors for a day, then spray it on the leaves of lettuce (this mixture normally keeps aphids at bay too, otherwise use the Marseille soap mixture as described elsewhere in the site. ).
For snails, you can adopt the appropriate traps (on the market) or (recommended) made by you made with bowls filled with old beer; since they are attracted by this drink, they approach and drown. For the cabbage worms, a mixture can be prepared with 1 part vinegar and 3 of water; add a tablespoon of liquid detergent and put the ingredients in a spray bottle; this mixture can be sprayed on the leaves to remove the pests.
For better phytosanitary control and better organoleptic quality it is advisable to always associate the lettuces (see: How to associate and why); this is one of the consociable plants with almost all vegetables (except sage).