How much sunlight does lettuce need?– Most lettuce varieties need 6 to 8 hours of adequate sunlight every day. Although this requirement greatly varies with variety, climatic conditions, and time of the year. The intensity of sunlight is more important than the timing. You can easily grow lettuce throughout the whole year without much care. Also, the availability and intensity of sunlight differ year-round.
So on hot summer days, indirect bright sunlight is good instead of direct full sunlight. Indirect sunlight simply refers to some sort of shade used to prevent direct sunlight from reaching the ground. Usually, we use green nets or cover clothes. Now, what exactly does full sun means for a gardener. Let’s check it out.
Check out my previous post: What to do with the Zucchini Plant at end of the Season?
What is Full Sun?
The full sun simply means direct sunlight. As per a gardener’s perspective, it denotes a minimum of 6 hours of direct sunlight daily. 6 hours of direct sunlight is sufficient for most plants. But this timing does not indicate the intensity of light being received by the plants.
This timing for daily sunlight availability can be divided into three portions. The first is Fresh morning sunlight that indicates direct sunlight from early morning. Next is noontime light which means mid-day availability of direct sunlight. Finally, you will have late light that denotes cool evening sunlight.
So whenever we say full sun then this can denote any of these three timings. The 6-hour timing may be the same but the intensity differs a lot in these cases.
Therefore if your lettuce receives morning or evening light then 6 to 8 hours is sufficient. Else only 3 to 4 hours of direct sunlight at noontime is enough to grow lettuce.
Does Lettuce Need Full Sun?
Yes, Lettuce does need full sun to grow. Although a partial shade with indirect bright light is better for the summer season. If you grow lettuce early in the spring season then a full 6 to 8 hours of direct sunlight is necessary. This will maintain the warmth for the faster growth of lettuce.
In the summer season, it is better to avoid direct sunlight, especially at noontime. All your lettuce will grow fine If it gets 3 to 4 hours of direct sunlight in the morning and evening. Else you may have to protect the lettuce from harsh burning sunlight in the noon.
You can use an overhead shade during the summer season to prevent sunburn. A green net or Shade cloth is ideal for covering the plants. These green nets or shade clothes are available in variable densities of 10% to 90%. Shade cloth with 30% to 50% density is good for leafy vegetables like lettuce. It will only allow 50-70% of sunlight to reach the surface.
Also Read: Does Lettuce Need Lots of Water?
How Often Does Lettuce Need Full Sun?
Lettuce is a cool weather leafy vegetable. It will require 6 to 8 hours of full sun in spring conditions. 6 to 8 hours of direct sunlight especially around early morning is ideal for lettuce plants.
Although it is better to allow partial indirect sunlight during the summer season. Summer days can be really hot especially in southern areas. The temperature can rise above 75 degrees Fahrenheit which is not good for lettuce.
The ideal temperature to grow lettuce ranges between 45 to 74 degrees Fahrenheit or 16 to 20 degrees celsius. Lettuce is comfortable in a cooler environment. If the temperature is cooler than 70 degrees then lettuce will need full sun for more than 6 hours every day.
How much sun does Lettuce need?
Lettuce needs 4 to 6 hours of consistent sunlight to maintain its temperature. The exact need depends on the intensity of sunlight rather than its timing. So in summer days 4 or 5 hours is enough as compared to 6 to 8 hours in early spring.
The whole idea of sunlight is to maintain enough temperature for good growth and proper light for photosynthesis. These natural processes are directly dependent on the intensity of light.
On summer days the sun is hot and bright enough to increase the temperature above 70 degrees Fahrenheit. Lettuce plants can survive this much temperature but it can cause some stress to the plants. This stress can force the lettuce to bloom prematurely. This phenomenon is called Bolting or Bolt formation. Here you will find sudden elongation in the central stem without many leaves formation. You have to use some shade to avoid this situation.
Does lettuce need direct sunlight?
Just like any other plant, lettuce also needs direct sunlight. In fact, direct sunlight is necessary for proper growth in any plant. Lettuce needs direct sunlight although it grows better in partial shade with bright light.
Direct sunlight is necessary especially in the early days of the spring season. This is the time of the year when the temperature can fluctuate between 40 to 60 degrees Fahrenheit. Lettuce seeds can germinate at 45 degrees Fahrenheit but require bright direct sunlight for 6 to 8 hours every day.
If you are growing lettuce in the mid-year time around summer. Then it is better to provide some shade to avoid bolting in lettuce plants. A partial shade with indirect bright sunlight can save your lettuce from the hot sun and also extends the harvesting season.
Does lettuce do well in shade?
Lettuce is one of the few green vegetables that grow well in shade. Partial shade is sufficient to grow lettuce although it requires full sun for 6 or more hours.
Shade has many advantages for the lettuce plants. The first and most important benefit is protection from hot sunlight. Next, it prevents animals and birds from feeding on these tender sweet lettuce leaves. proper shade can easily extend the harvesting season up to 4 weeks. You can harvest more especially if you grow leaf-type lettuce instead of single harvesting head lettuce.
Lettuce Varieties for Partial Shade and full Sun
There are five main varieties of lettuce plants. Some are obviously popular than others due to their unique taste, texture, color, and tenderness.
Some popular heat and shade friendly lettuce varieties are-
Crisphead: Sierra Batavian, Nevada, Michelle.
Romaine: Coastal Star, Anuenue, Jericho, Little Gem
Bibb: Buttercrunch, Summer Bibb
Leaf: Green Star, Bronze Arrow Lose Leaf, Black Seeded Simpson.
Butterhead Lettuce
Stem Lettuce
Parris Island Cos is another popular bolt-proof lettuce variety.
Check out these lettuce seeds on Amazon.
Does lettuce need sun or shade to grow?
Lettuce needs bright sun as well as some shade to grow. In fact, it is one of the few vegetables that can easily survive in partial shade. Most lettuce varieties do better in partial shade with bright light. Full sun for a long duration can sometimes harm the plant. Especially if the intensity of light is too much to handle.
Overall you can easily grow lettuce in full sun or partial shade depending on the time of year. The current climatic condition is the main governing factor to decide about the shade or full bright direct sunlight for lettuce plants.
What will happen if lettuce gets too much sunlight?
Too much sunlight is not good for the lettuce plants. It can dehydrate quickly. The leaves can turn yellow. They will lose their sweet taste. All these conditions can stress the plant and eventually it will bolt. In simple words, the stress can force the lettuce plant to form flowers and seeds prematurely. The ultimate goal of a plant is to maintain its heredity. Especially in the time of stress, the plant will focus on seed formation to continue its generation.
Therefore the lettuce will slow down leaf formation, uses all sugar deposits, and form long flower spikes. The leaves as a result will taste bitter.
- Bolt formation- Flower and seed formation.
- The leaf becomes bitter in taste.
- Stop new leaf formation.
Can I grow lettuce in full shade?
No, you can’t grow lettuce in full shade, at least without any support. In fact, you will need lots of artificial grow lights to provide sufficient lighting to your lettuce.
These days indoor farming has become a popular part of urban gardening. Lettuce is a popular choice for every urban gardener. So in absence of open garden space, they have shifted to indoor farming techniques. Especially indoor Aquaponics with grow lights is used to grow lettuce in full shade.
So Technically we can say lettuce can be grown in full shade with artificial grow light. You can grow lettuce anywhere anytime with these modern techniques. Environment control is easier in indoor spaces than open garden areas.
Final Words
What’s your opinion on How Much Sunlight Does Lettuce need? 6 to 8 hours of direct sunlight is sufficient although it greatly depends on the time of year. Summer days are hotter than spring and autumn. So adjust lighting according to the intensity required by the lettuce plant. Different varieties have different needs. Therefore choose only the best heat tolerant and bolt proof lettuce varieties in summer.
