With some planning, regular planting and correct variety selection it’s possible to grow lettuce all year round. With the protection of a greenhouse, cloche or fleece you can have lettuce growing into the coldest winters.
Most lettuce are ready to begin harvesting in 50 days with cut and come again or leaf lettuce varieties often ready far sooner than this. Succession sowing is essential.
When it comes to taste home grown lettuce is often sweeter, crunchier and and juicer. It’s also been proven that home grown lettuce is far better for your health with a far higher amount of vitamin A.
Choosing Which Variety To Grow
There are a lot of varieties of lettuce available, so choosing the right one for you is important. There are two different types: heartening lettuce and loose-leaf lettuce.
The main difference between the two types of lettuce is the way they grow their leaves. Heartening lettuce grows a lettuce head or heart where the leaves are layered on top of each other. Loose-leaf lettuce, as the name suggests, grows more loose leaves, which means you can harvest individual leaves as you need them.
- Heartening lettuce is divided into three types:
- Cos lettuce, sometimes also called Romaine lettuce: this type grows into oblong lettuce heads, such as Little Gem lettuce
- Butterhead lettuce: this type produces a more open shape, such as the All Year Round lettuce
- Crisphead lettuce: this type has a large heart with curled, crisp leaves, such as the classic Iceberg lettuce
Loose-leaf lettuces come in a variety of shapes, flavours and colours. And while the choice of the type of lettuce you grow is down to your own preference, loose-leaf lettuces are more suitable for small spaces and growing in containers.
Here are some favourite lettuces varieties for you to try:
Little Gem: this well-known lettuce variety is a cos type and produces sweet and crunchy leaves in a very compact head
- Ideal for salads
- Produces compact crunch lettuce
- Resistant to root aphids
Red & Green Salad Bowl: this non-hearting lettuce variety produces red and green leaves and will give you salad all summer long
- Organically grown seed
- Oak leaf shape red and green lettuce leaves
- Colourful tasty leaves
All Year Round: this butterhead variety is great for sowing all year round
- Favourite 'butter head' with a long harvest season
- Good flavour
- Slow to bolt in hot dry weather
Lambs Lettuce Favour: another loose-leaf variety, which is also known as corn salad, has a mild flavour
- Known as 'Corn Salad
- Neat rosettes of small, upright leaves
- Shiny and tender leaves with a distinct, mild flavour
Preparing The Ground
While lettuce plants aren’t very fussy about soil conditions and are generally a tolerant crop, they need a constant supply of water, so water retention in the soil is important.
Dry soil can cause the lettuce to bolt, which means they start to produce seeds. Once this happens, they will put all their energy into growing the seeds rather than the leaves, which will stunt your yield.
You want to prepare the ground about two weeks before you sow your lettuce seeds or plant on your lettuce seedlings. Mix your garden soil with well-rotten garden compost, shop bought compost or blood, fish and bone fertiliser to add vital nutrients. I have used this one before and was very happy with it.
When & How To Sow Lettuces
Lettuce is a cool-weather crop, its ideal germination temperature is between 2°C and 19°C. Lower soil temperatures will slow down germination, whereas if your soil temperature is higher it will decrease the chance of germination.
Your seed packet will tell you when to sow your lettuce seeds, but here is a general guide of timings:
- January/February: sow indoors in seed trays to harvest in early summer
- March – July: main growing season; sow outdoors, but protect your lettuce plants from hard frosts, for example with cloches, in early spring. From late March on you can also start to plant on your lettuce seedlings you started off indoors
- August: sow outdoors for winter harvest; protect your plants with cloches when the weather gets colder, normally from September onwards
- September/October: sow indoors to harvest in spring; make sure you choose suitable varieties for winter harvest, such as ‘Winter Density’
Seeds should be sown just less than half an inch (1cm) deep and covered with a thin layer of very fine soil or compost.
Spacing for lettuce depends on the type grown, leaf lettuce should be about 4 inches (10cm) apart, cos and loose leaf varieties should be 8 inches (20cm) and large icebergs should be 12 inches (30cm) apart. For winter planting increase these spacings by at least 2 inches (5cm) to allow for extra airflow and prevent any mould or rot.
Rows should be 12 inches (30cm) apart but for small plants or in good soil can be planted closer.
It’s important to keep sowing lettuce regularly to achieve a continuous crop. Growing a few different varieties will ensure your harvest dates vary and cropping extended. In the Spring making new sowings every 2 weeks will keep the lettuce leaves coming while more slow growing winter varieties should be sown monthly. This will guarantee you a steady supply of salad!
Growing Lettuce Plants On
If you have grown your lettuce from seed in trays, then your seedlings will be ready to transplant when the first true leaves appear. True leaves are the second pair of leaves that grow, they resemble the look of the adult plant leaves. The first leaves that grow from a seed are called seed leaves and they are not able to perform photosynthesis, the way plants produce food for themselves.
In terms of timings, you can plant out your seedlings once heavy frosts are over, normally later March.
Lettuce are not really fussy about the soil they are grown in as long as it’s reasonably good. Being fast growing lettuce really like to get a lot of their food from liquid fertilisers, a general purpose feed or a good mix of liquid seaweed 3 weeks after transplanting and again after 5 weeks will give incredible growth. I use this seaweed feed regularly for most of my vegetable plants.
- Seaweed plant food promotes strong growth, increased crop yields and lush foliage
- Contains a high concentration of seaweed, known for its unique anti-stress compounds
- Also include extra iron and plant based amino acids that feed plants and improve yield
If you expect to harvest within 7 days do not feed.
It’s important to keep lettuce plants well ventilated when they are in a greenhouse, cloche or under fleece. During warm days remove the plants protection for a few hours to allow fresh air to circulate around the plants.
Weeding of lettuce should really be done by hand once every two weeks. Small weeds should pull from the soil by hand easily and won’t damage the lettuces’ shallow roots.
Make sure you water your lettuces regularly, especially in hot weather, to avoid the soil getting too dry, as this will cause them to bolt, produce seed. In hot weather, the best time to water your plants is early morning to give the water chance to reach the lettuce roots.
Apart from regular watering you can also help the soil keep the moisture in by covering the area around your lettuce plant with mulch. This will also feed your plant, Hurray!
If you have sparrows in your area or garden, then make sure you protect young lettuce leaves from them. They absolutely love them! You can cover them with fleece or garden netting.
Harvest your plants regularly.
Cut and come again lettuce should be picked from weekly. Once the plants begin to look tired another sowing should take over. Cut and come again lettuces grow quickly so multiple sowings a year can be made in the same ground.
It’s easy to tell when head lettuce are ready by squeezing the lettuce to see if the head is firm. Once the head is firm do not leave in the ground more than another week or two as they will quickly bolt and go to seed.
After harvesting if you quickly place the lettuce in a plastic bag in the fridge it will often last a week to ten days. Cut and come again types will usually wilt faster so should be eaten within 5 days. Long term storage of lettuce isn’t possible.
The best time to harvest lettuce is early in the morning, before the leaves lose some moisture which will make them less crisp.
Pests and diseases affecting lettuce
While lettuce is fairly easy to grow, it is susceptible to some pests including aphids and some fungal diseases.
Slugs and snails love crispy and juicy lettuce leaves. Clearly, they have good taste! They are often described as ‘gardeners’ enemy number one’ because most plants in our gardens, not just vegetables, are on their menu.
However, slugs and snails are vital for our ecosystem, so wherever possible try to tolerate them. Don’t use slug pellets, as they kill them and can also affect other wildlife.
Of course, you don’t want them to ruin all your hard work and keep you from enjoying delicious salad, so here are some tips to keep your lettuce safe from slugs and snails:
- Slugs and snails mainly eat young plants, so you can protect your lettuce seedlings by covering them with cloches until they are big enough not to attract too many slugs and snails.
- Companion planting: there are plants that slugs and snails don’t like and will avoid. So if you plant these plants around your lettuce, they will be safe. These plants include lavender, rosemary and sage.
- Harvest your leaves as soon as they are big enough to eat and lettuce heads as soon as they are firm.
- If you spot a slug or snail on your lettuce, pick it up and move it to a part of the garden where it cannot do as much damage. I have a wild area in my garden, where slugs and snails are welcome. The best time to do that is a couple of hours after dusk. You might need to use a torch.
Another pest that might affect your lettuce plants are lettuce root aphids. Unlike other types of aphids these feed on the lettuce roots rather than the leaves or stems. This means you won’t see them above ground. They are most active in mid to late summer and signs that your lettuce suffers from a root aphid infestation are:
- Your adults plants suddenly wilt and die
- Like other aphids, these are also ‘farmed’ by ants, who like to drink the honeydew the aphids produce. So if you notice a lot of ants around your lettuce, root aphis might be in the soil
When it comes to aphids, prevention is the most effective thing to do, especially when they are underground and therefore not visible above ground. Here are some tips on how to prevent and aphid attack on your lettuce roots:
- Root aphids prefer dry conditions, so regular watering, especially in dry weather will minimise the risk of an infestation.
- If you think your lettuce is affected, you can carefully pull out the plants and check their roots. Make sure to only pull out plants that are big enough not to get damaged by this. If you see any aphids, wash them off with water. Then replant the lettuce in fresh compost, never in the same place as the aphids will be in the soil. Cultivate the soil to expose the aphids which will make them an easy meal for natural predators such as ladybirds.
- You can also use insect-proof mesh to prevent the aphids from reaching the lettuce roots. I used this Environmesh before and it worked well.
Grey mould is a fungal disease that often affects damaged plants, which have cuts or tears. It favours humid conditions and can occur all year round.
You will see a fuzzy grey-brown mould developing on the leaves. Any infected leaves should not be eaten. Destroy them as soon as you see them but don’t compost them. If the stem is also affected, the plant will turn yellow-brown and develop into slimy rot.
Here are some tips to prevent grey mould from affecting your lettuce plants:
- Grey mould thrives in humid conditions, so ensure good air circulation by planting your lettuce well spaced out.
- Water from underneath to avoid the leaves getting wet and water in the morning
- Later in the season, if you grow your lettuce outdoors under cloches to protect them from frost, make sure you remove the cloches during the day in warm weather to reduce the risk of humidity. If you grow in a greenhouse, keep it well ventilated, even in cold weather.
- The fungus enters most easily through cuts or tears, so try to keep slugs and snails away from your plants to avoid damage
- If you spot any signs of grey mould, remove the affected leaves immediately and destroy them, do not compost
- Keep the area around your plants free from dead plant material to minimise the risk of grey mould affecting your plants.
Leaves infected by grey mould are inedible. If you remove the outer leaves of a lettuce head as soon as you spot any signs, the rest of your lettuce should still be good to eat. But check for signs after you have removed any infected leaves to be sure.
Another fungal disease that can affect lettuce is lettuce leaf drop. It is most prevalent from summer to early autumn and favours wet soil conditions. Symptoms of lettuce leaf drop are when a plant suddenly turns yellow, wilts and collapses and on the underside you will see a soft white mould develop. You might also notice the smell of rot.
Heavily infested plants cannot be eaten!
Here are some ways to minimise the risk of lettuce leaf drop affecting your plants:
- Space your plants well apart to ensure good ventilation and plant them in a sunny spot to prevent humid conditions
- Weed regularly around your lettuce plants, ideally by hand, to help the area to dry quicker after rain
- Mulching your plants can help minimise mud splashing on the leaves when it rain
- Water your lettuce from underneath, to avoid the leaves getting wet
- Practice crop rotation as the spores can overwinter in the soil, which will then affect next year’s plants
- Remove any infected plants and destroy them, but do not compost them, as the spores can survive and infect your compost
Lettuce downy mildew is a fungus-like organism that affects lettuce. Infected plants develop yellow patches and white mould on the underside of the leaves. The plant will turn brown as the leaves die.
The disease is active outdoors from early summer to mid-autumn, but indoors it can strike all year round. A plant that is infected with lettuce downy mildew can also attract grew mould.
Like with most diseases, prevention is the best way to keep your salad safe:
- Ensure good circulation of air as humidity encourages downy mildew
- A sunny position will ensure the leaves dry out quickly after rain
- Practice crop rotation to avoid any spores that overwintered infecting new plants
- Remove any infected plants immediately. Often the disease only affects the out leaves, leaving the rest of the lettuce head unaffected and therefore good to eat. Remove the entire plant once you harvested the lettuce heads to avoid the soil getting infected which could then spread to other lettuce plants
Luckily, many ways to prevent one disease also prevent the others, so keeping your lettuce disease free is not too much work.
Frequently Asked Questions
If you didn’t find what you were looking for in the article, you might find the answer in our FAQ section.
Does lettuce need full sun light?
Lettuce is a cool-weather crop, so doesn’t like it when it gets too warm. Early in the season and from autumn onwards a sunny spot works well.
But during mid-summer partial shade is better for your lettuce. As too warm weather will cause the lettuce to bolt, which means they produce seeds and will stop growing new leaves.
Generally though, lettuce is not too fussed. My recommendation would be to plant your lettuce in a spot where it gets the morning sun, but is in shade the rest of the day. This will work all year round.
But you want to keep an eye on humidity levels from autumn to avoid diseases like grey mould.
Can I grow lettuce in containers?
The short answer is yes. But make sure that you use a container that is at least 15 cm deep, as their roots are quite long.
The container, pot or grow bag you use should have plenty of draining holes to allow excess water to run off.
Try not to cram too many plants into one container though, as this will prevent air from circulating. And this is important to avoid fungal diseases. Always thin out your seedlings.
Water your lettuce regularly when growing in containers or bags to prevent the soil from drying out as this can cause the plants to bolt and also increases the risk of lettuce root aphids infesting your lettuces.
You can use multi purpose compost. Fill the container full to the edges, then water well. Watering before you sow the lettuce seeds will ensure that you don’t wash them away.
Sow the seeds thinly then over them with a thin layer of compost and lightly tap the soil. Keep the surface of the soil moist until the seedlings have grown their first true leaves. The best way to do this is by spraying the surface with water, rather than watering with a watering can.
Once the seedlings are stronger, thin them out and start watering them directly at the soil, rather than from above to keep the leaves as dry as possible.
Harvest cut-and-come-again varieties as soon as the leaves are big enough and lettuce heads when they are firm.
If you don’t have much space, but want the taste of fresh lettuce, you can grow loose leaf lettuce varieties in window boxes. Again, make sure you water them regularly.
Can I grow lettuce indoors under lights?
Yes you can. But you will need a good grow light that is made for the purpose of growing plants. Because plants need certain wavelengths of light to be able to photosynthesise, such as the blue and red ranges.
Therefore, growing lights can be expensive. For an experiment, I tried this grow light which wasn’t too expensive and it worked well.
- 【3-year Warranty】Updated Package(2020): 1x Grow light, 1x Thermometer Humidity Monitor, 2x Adjustable Rope, 1x Hanging Kit, 1x Power Cord, 1x User Manual. We offer a 3-year warranty and 30-day money-back guarantee. If you have any problems, please contact us.
- 【Optimal Full Spectrum】Different from others, this led grow light added 2PCS Yellow LED, is beneficial to the synthesis of photosynthetic pigments, promoting energy transmit, improving plant growth quality. It also has universal Blue, Red, IR, UV, White light. Blue and red led are an essential light for all plant growth. Expensive IR UV led can promote plants to defense mechanisms.
- 【Wide Coverage】60PCS SMD led(total 600W) provides uniform illumination. It can replace traditional 600-watt HPS/MH while consumes only 80 watts. Ensures maximum yield with minimum power usage and heat. PAR 436umol/m2s at 24” height, perfect for 2x2ft growing area(Maximum coverage area at 4x4ft at 24” height).
Can I grow lettuce without soil?
It is possible to grow lettuce and any other plant without soil. Plants need air, water and nutrients to grow. Soil provides these things and that’s why it is used.
But as long as you can create an environment that provides the roots of a plant with these three elements, you don’t need soil. There is a science looking into this called hydroponics.
An easy way to grow plants without soil is to plant them in a pot with perlite and water them regularly with water containing a liquid fertiliser. The air is held between the perlite that will ensure the roots won’t suffocate.
As long as you don’t let the perlite dry out, the plant should grow, in theory. As I said, hydroponics is a science, so it is not easy to do.
You can buy hydroponics growing systems that let you grow vegetables and herbs without soil. Most of them include a growing light, so you can grow your plants anywhere. Like this one for example.
- Growing All Year Round: The LED growing light of iDOO indoor hydroponics system, only 23W, which simulate the sunlight spectrum, promote veggies photosynthesis in any weather and and help plants maintain their optimal growth status. You can plant fresh herbs, flowers, etc. throughout the year without seasonal/weather limitations.
- Auto Circulation System: iDOO hydroponics growing system is designed with a water and air circulation system, on/off automatically, avoiding the plant rotten roots caused by hypoxia. Also, you can swicth to sleep mode, enjoy a deep sleep.
- Smart Grow Modes with Timer: Turn on/off automatically design. For leaf plants growing harvest leaves, choose Vegetables Mode which contains blue light. For fruit plants growing stronger, choose Flower&Fruits Mode which increases the red light.
It sounds like a very fancy idea and if you don’t mind spending the money probably worth a try.