Today we’re going to talk about how to cultivate romaine and canasta lettuce, the two most consumed varieties in Italy. The organic cultivation of these lettuce varieties holds many secrets. It’s important to pay attention to all the details, starting from sowing and soil preparation, all the way to irrigation systems and organic pest defense. These secrets are relatively easy to apply. Discovering the ease of organic cultivation and, most importantly, the taste of a salad grown in your own home garden, you won’t need to buy this vegetable, which is always on the table, from the supermarket anymore.
But let’s proceed in order and first explore the origins and nutritional properties of lettuce.
Lettuce: Origin, Nutritional Properties, and Varieties
Lettuce, scientifically known as Lactuca sativa, belongs to the Compositae family. It’s commonly known as “insalata” (salad), but it’s more accurate to call it lettuce, as “insalata” mainly refers to the preparation made from this vegetable. It’s a vegetable that was cultivated during the times of the Greeks and Romans, making its origin Mediterranean. The scientific name “Lactuca” comes from Latin. When this plant is freshly cut, it emits a milk-like liquid at the base of the head (in Latin, “lactis”).
Nutritional Values and Properties
Lettuce is composed of 95% water, making it an essential component of low-calorie diets. Besides being low in calories (only 15 per 100 g), it’s rich in minerals such as phosphorus, potassium, calcium, magnesium, and iron, as well as vitamins A, B, C, and E. These characteristics give it excellent diuretic and antioxidant properties. Lettuce is recommended in the diet for those who suffer from diabetes as it helps regulate blood sugar levels. It can also be used by those dealing with water retention or to aid in the elimination of kidney stones.
Main Varieties to Cultivate
The varieties that adapt well to the cultivation conditions in our country are romaine lettuce and canasta lettuce, but there are many others as well.
Romaine lettuce is probably the most widespread and commonly used variety. It features a long, narrow head that is quite voluminous. Its bright green leaves are wavy. The texture is crisp, and the taste is quite sweet. Within the broader family of romaine lettuce, there are further varieties with differences in color, texture, growth cycle, and other characteristics. Here are some examples:
- Verde degli ortolani (Ortolani’s green);
- Bionda degli ortolani (Ortolani’s blonde), with less thick leaves and a lighter color;
- Marvel, also known as “meraviglia delle quattro stagioni” (marvel of the four seasons), with a bright red color and a bolder taste;
- Gigante bianca (Giant white);
- Gigante rossa (Giant red);
- Bianca d’inverno (Winter white).
In any case, it’s important to always choose varieties that best suit your specific conditions, especially in terms of climate and cultivation period.
Another well-known and appreciated variety is Canasta lettuce. It has a wider and more compact head compared to Roman lettuce. It also has a clear central heart that fills up, surrounded by fleshy outer leaves. Compared to Roman lettuce, Canasta grows more in width than in length. The taste of Canasta lettuce is stronger compared to its cousin Roman lettuce, making it preferable for mixed salads. The color of the leaves tends to be reddish towards the outer parts, although this depends on the type of Canasta lettuce. Among the different varieties, we highlight:
- Ubriacona, a variety typical of the Umbria region;
Cultivating Lettuce in the Garden and in Pots
As mentioned in the introduction, unfortunately, a large portion of the lettuce we find in our supermarkets comes from abroad. Specifically, there’s a place in Spain, the Almeria greenhouses, where an expanse of intensive vegetable cultivation greenhouses stretches as far as the eye can see. The reflection we want to make is this: why buy a vegetable from thousands of kilometers away when it can be easily grown in any garden or balcony? Why do it with the knowledge that the product is most likely not organic and requires chemical fertilizers and systematic pest treatments to be grown so intensively?
Homegrown Roman or Canasta lettuces have nothing in common with a commercial product, which has a neutral taste and is transported in plastic bags for thousands of kilometers. A DIY cultivation, perhaps using soil or compost obtained from home composting, with pest defense using natural remedies, is unmatched in terms of taste and quality. Since lettuce is mostly composed of water, it’s the soil that imparts flavor, making it unique and appealing for all types of diets. Even in a simple pot, in a balcony garden, you can achieve great results with your organic lettuces.
Climate and Seeding Period for Lettuce
In general, we’re talking about a plant that’s quite resistant to different climatic conditions. It can be cultivated in open fields from spring to autumn. However, there are certain varieties that are better suited to specific climates and temperatures.
For example, Roman lettuce is sensitive to heat, which accelerates its maturation. Therefore, this variety prefers a cooler climate to mature properly. Consequently, the Roman type is more suitable for autumn and early spring cultivation.
Canasta lettuce, on the other hand, thrives better in a mild climate. It has a slower maturation, making it adaptable to warmer periods such as spring and summer. Seedlings are sown in seedbeds from February to May for spring and summer cultivation and in August/September for autumn seeding. Pay attention to the seeding times, as starting from seed prolongs the growing period. A seed needs at least 20-30 days to develop into a transplantable seedling, depending on the season. The advice is to plan a staggered seeding, meaning not to transplant an excessive number of lettuces at the same time. This is because once lettuce reaches full maturity, it should be harvested promptly. The longer you wait, the higher the risk of pest attacks and rot formation. By spacing out the seeding and transplanting every 15 days, you can achieve a production rhythm sufficient for family consumption, always fresh and of high quality.
Soil and Fertilization for Lettuce Cultivation
The ideal soil for lettuce cultivation should be loose, soft, and well-tilled, with no waterlogging. As for fertilization, the plant requires well-fertilized soil with a good nitrogen concentration. Therefore, it’s advisable to cultivate it in soil that previously hosted a leguminous crop or to apply organic fertilizer before seeding using pelletized manure (available here). Organic fertilization should be done approximately 10-15 days before transplanting. This will provide your organic lettuces with all the necessary nutrients throughout their cultivation cycle.
Irrigation and Spacing
Regarding the water needs of Roman lettuce and Canasta lettuce cultivation, a distinction should be made. In an autumn cultivation of Roman lettuce, for instance, there won’t be a need for frequent irrigation support. Therefore, it might be convenient not to set up an irrigation system. On the other hand, for spring and summer cultivation of varieties like Canasta, using drip irrigation is beneficial. This allows for consistent irrigation. You can find an excellent drip hose with a dripper emitter here. As for transplant spacing, lettuce cultivation generally doesn’t require a lot of space. The irrigation system shown in the image above involves placing four drip hoses at 25 cm intervals along a linear meter of land. The seedlings should be spaced 20 cm apart along the row. Compact spacing benefits cultivation by allowing the plants to support and shield each other. Too much space between the plants, especially with Roman lettuce, increases the risk of leaf expansion and damage. In any case, pay close attention to irrigation. While the plant needs consistently moist soil, it’s also vulnerable to waterlogged conditions, which can lead to rot.
Mulching is essential for maintaining healthy lettuce cultivation. This plant is particularly sensitive to the presence of weeds, which can hinder its growth. The problem is especially prominent at the beginning of growth. Therefore, you need to carefully weed as necessary or apply mulching. Mulching can be natural, such as using straw. Alternatively, you can opt for artificial mulching using perforated plastic sheeting, non-woven fabric, or biodegradable fabric.
Since lettuce is a fast-growing crop with minimal soil disturbance and waste, a well-preserved plastic sheet can be reused many times. In addition to preventing weed growth, mulching significantly reduces water usage. It also keeps the soil consistently moist and encourages the growth of microorganisms.
If you’ve implemented staggered seeding, your harvesting should also follow suit. Be careful not to let your lettuces over-mature, especially Roman lettuce. If not harvested in time, Roman lettuce tends to fold in on itself and develop rot at both the base and the apex. Harvest your lettuces, ideally starting when they are not fully mature. This will provide the right progression. However, if you want to collect seeds from your lettuces, allow them to flower and produce seeds. Lettuce is a biennial plant, and it blooms and produces seeds in the second year.
Biological Pest Defense for Lettuce Cultivation
Starting with the most significant issue: the sworn enemies of lettuce cultivation are slugs. If you’re looking for advice on keeping snails and slugs away from your garden, check out this detailed article.
In general, if cultivated with the precautions we’ve discussed, lettuce isn’t particularly susceptible to pest attacks.
Using natural infusions, such as tomato infusion, nettle infusion, and garlic infusion, preventively, you can effectively keep away pest insects like whiteflies or aphids. Be cautious, as mentioned before, with water stagnation, which can facilitate the development of fungal diseases like Botrytis. In this case, instead of applying infusions, it’s recommended to maintain proper cultivation conditions, such as limiting irrigation to prevent waterlogging and rot.