How to grow Lettuce guide. The Quickcrop all lettuce mix contains a broad range of easy to grow lettuce, ideal for cut and come again use. It's great to enjoy your own lettuce over the summer but imagine how uplifting it would be if you could treat yourself to home-grown salad during the colder months. The good news is that several lettuce varieties can tolerate cool conditions. Red Salad bowl Lettuce is a slow bolting red oakleaf. Deep-red fine divided leaves. Sweet flavor and tender. Maturity 50 days.
Where to grow lettuce:
You'll need some cloches – transparent frames that make the most of weak sunlight and the plants' own heat, warming the crop and its soil. A collapsible poly-tunnel is a handy alternative to a rigid cloche. Cloches available at our e-shop soon.
A moist well drained fertile soil which has had plenty of compost dug in the previous autumn is best.
When to grow lettuce:
Start early indoors or seed directly outdoors from late March to August. Cover with 1/8 inch light soil.
Seedlings started indoors can be planted outside after danger of severe frost has passed. From trays or modules harden off and plant out under fleece. Make a hole with a dibber or suitable stick approx 9in apart (A piece of an old broom handle is ideal). Place the seedling plug in the hole and firm gently around the roots, water well.
There are many different types and varieties of lettuce but with regard to sowing we either want one single head of lettuce or a bunch of plants for cut and come again production. I always like to sow in modular trays but I find it especially good for lettuces as emerging seedlings are so prone to slug attack. Important: Many lettuce varieties fail to germinate when the temperature of the compost is above 25°C. When raising seedlings in a greenhouse or polytunnel this can often happen in the spring and summer. Place the seedlings in a cool shed for 2 days to germinate. Once they have germinated put them back in the tunnel, temperature is not an issue once the plants are up.
Sowing in Modular trays
Use a seed compost which has a finer texture and lower nutrients than your standard multipurpose compost. We use a seed module tray with each section being approx 2 inches deep. Here's what you do: Fill the seed tray with compost and brush off any excess. When filling the tray rub the compost through your hands to break up any lumps. Give the tray a sharp bang on your table to settle.
Don't make holes!With your fingers make very small depressions in each cell. Lettuces need light to germinate so we will not be burying the seed, the depressions should be just enough to keep the seed in the middle of the cell.
Single head or cut and come again? If you want a single head of lettuce sow 1 seed per module. If you are growing a 'mat' of lettuce for cut and come again sow 3-5 seeds. Make sure you have the right variety for each.
Don't cover seeds I know you'll want to but don't cover the lettuce seed or you'll get a very poor germination rate. You will need to keep the compost moist at all times just don't cover them. Gently water your seeds. A good tip is to use a plastic bottle with small holes punched in the cap. This is less likely to wash the seed around than the heavy spray from a watering can.
Place your trays in your greenhouse, polytunnel, cold frame or windowsill to germinate. They should be ready to plant out in about 4 weeks.
Hardening off lettuce seedlings
It is crucial to harden off lettuce raised indoors before planting out. Plants that have been raised indoors will need to get used to the outdoor temperature and conditions before they can be planted outside, this will take about a week to 10 days depending on the weather. The best way is to use a cloche or mini greenhouse. You can leave the cloche off the plants on dry frost free days and replace at night. Gradually increase the time with the cloche removed until the end of the week when you leave it off day and night. If the weather is mild you may not need the cloche, just move the plants outside for longer periods each day. If you have started your seeds on a windowsill you will need to leave them in an unheated room for a day or two before moving outside to the cloche.
The spacing for lettuce varies depending on what you're planting:
- Small Lettuce (Little Gem) 20cm between plants and 20cm between rows.
- Medium Lettuce (Lollo types, butterheads) 25cm between plants and 25cm between rows.
- Large Lettuce (Iceberg) 35cm between plants and 35cm between rows.
- Cut and come again multiplugs 25cm between plants and 25cm between rows.
It is important to plant lettuce with its seed leaves above the ground. The seed leaves are the 2 lowest leaves on the stem. If these leaves are buried the stem is likely to rot and you'll loose your lettuce plant. If your lettuce seedlings have gone a bit leggy (have a long stem) you can plant a bit deeper to cover the stem but never further than the seed leaves.
Lettuce of one sowing will usually be all ready at the same time. The plants quickly run to seed and don't store well so only sow what you need week by week. Butterhead or crisphead lettuce is harvested by cutting the whole head at the base of the plant. Loose leaf types and cut and come again mixes can be harvested a number of times. remove the outside leaves of the plants and the centre will continue to produce new leaves for 2 or 3 cuts.
Top Tip: The earlier in the day you harvest your lettuce the longer it will keep and the more nutritious it is. If you set your alarm clock for 6am and cut your lettuce it will keep in a plastic bag in the fridge for a week. Harvest at 2pm on a sunny day and it will be wilted already. Plants taki in moisture at night and let it out during the day.
Separate leaves and wash under cold water. A salad spinner is a worthwhile investment as dry leaves will keep in the fridge much longer. When lettuce is washed and properly stored, it stays fresh in the fridge for about 5 to 6 days. However, note that lettuce that you've washed yourself and stored properly will last longer then pre-washed lettuce.