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Lettuce

Crunchy lettuce is the unsung hero of the salad bowl. Select from the traditional Iceberg lettuce that is the backbone of sandwiches, wraps and hamburgers or Cos lettuce, the signature ingredient of the Caesar salad. If punch is required, try Radicchio, a bitter leaf that comes in a variety of shapes and colours including dark red. For a mixture of leaves try Mesclun which includes rocket, chervil, and mustard.

The nutrient level of lettuce will vary depending on variety selected, the humble Iceberg provides calcium, potassium, vitamin C and folate, while the red leaf varieties may also include biotin, omega-3 fatty acids, vitamin B2 and B6.

Lettuce varieties are easy to grow from seeds or seedling. Harvest times will vary between varieties and will depend on whether the whole plant is taken or just the leaves. Leaves can be harvested from six weeks on, whereas allow 10 to 12 weeks for the whole plant. To get a continual supply of leaves, plant another batch about 4 to 6 weeks later.

Lettuce belongs to the Asteraceae and daisy family which also includes sunflowers, chicory, globe artichoke and safflower. As lettuce is a quick crop make the most of garden space by growing alongside., grow alongside beets, carrots, strawberries, broad beans, parsnips or radishes.

Follow our seven easy steps to successful lettuce harvest including tips along the way.

How to grow vegetables - lettuce

When to plant and position in the garden.

Position.

Lettuce is thought of as a cool season crop but with new modern varieties they can be planted in all regions of Australia throughout the year.

Check hardware and garden centres to get the best local varieties.

Location

  1.  Lettuce are a cooler season crop so in cooler temperatures plant in at least six hours of sun a day.
  2. In summer, especially if areas are prone to high heat consider planting along side living shade such as beans or sweet corn or erect a shade tent to protect them.
soil TLC tips in summer

Soil

Get the soil right to harvest a bumper crop of delicious lettuce.

Follow our steps for easy soil preparation.

  • Turn the soil over before planting to a depth about 10cm.
  • Add heaps of well-rotted compost and manure for strong growth and great leaf favour. For a no-dig option consider Seasol Liquid Compost.
  • Lettuce can be grown in all types of rich, well-draining soil, with the PH around 6.5.
  • To boost the soil add Seasol Plant + Soil Booster and a fertiliser rich in nitrogen such as PowerFeed Controlled Release for Tomatoes & Vegetables.
  • Water in well and if possible, let the soil rest for two weeks or so.
  • Lettuces are surface rooting, so to prevent the roots from drying out plant into a layer of mulch.
How to grow vegetables - lettuce

Step 1 -Sowing seeds.

  • Check the back of the seed packet as different varieties of lettuce require different spacings.
  • In the soil, dig shallow (1cm) trench rows 20 to 30cm apart. Sow seeds every 10cm apart and backfill with soil.
  • In seed trays, put a couple of seeds into every cell or make shallow row 1cm deep and scatter a few seed along the rows. Lightly cover with seed raising mixture.
  • In pots 20cm deep and wide, make a few small holes 1cm deep in each corner of the pot. Scatter a few seeds in each hole and lightly cover with potting mix.
  • Water in well with Seasol to help increase seed germination rates.

Note: This is not lettuce seeds, it’s just an illustration to show seeds being planted.

How to grow vegetables - peas

Step 2 – First growth.

  • Seeds will start to emerge out of the soil within 10 to 14 days depending on the temperature. It may take longer if the temperature is cooler.
  • When seedlings sprout, they only have two leaves. These leaves look like two fat hearts on either side of the stem.
  • Lettuces require a lot of water to keep the leaves juicy and fresh so check moisture levels daily.
  • Apply Seasol weekly to help stimulate strong root development and healthy growth.

Note: This is not lettuce plant, it’s just an illustration to show seeds germinating.

Step 3 – Baby lettuce seedlings.

  • Thin out weaker seedlings so they are not competing for nutrients and space.
  • Lettuce leaves use a lot of water to keep them healthy, crisp and green so check moisture levels and water daily if required.
  • Apply a liquid fertiliser such as PowerFeed PRO SERIES for Tomatoes & Vegetables every week to the soil around the plants. Lettuces are a hungry crop, so they need the right blend of nutrients to encourage fast growth.
  • Thin seedlings again a few weeks later when they are around 10 to 15cm high. For leaf crops space at around 20cm apart, for the whole plant space around 30cm apart.

Step 4 – Lettuce seedlings ready for transplant.

  • If transplanting seedlings from seedling trays you have grown, the seedling should be around 10 to 15cm high. For leaf crops space at 20cm apart, for whole lettuce space around 30cm apart.
  • If transplanting seedlings from punnets you have purchased, check the seedling label for spacing and depth requirements.
  • Wateryour newly transplanted seedlings in with Seasol to get them over transplant shock.
  • Oncea week feed your lettuce seedlings with a liquid fertiliser such as PowerFeed PRO SERIES for Tomatoes & Vegetables.

How to grow vegetables - lettuce

Step 5. Lettuce plant growth.

  • Watch your lettuce leaves grow over the following weeks as the rosette starts to form.
  • Lettuce leaves like to stay moist to stay juicy. If the soil dries out, the plant may bolt and go to seed.
  • Check mulch around plant and apply more sugar cane or pea straw if required.
How to grow vegetables - lettuce

Step 6 – Lettuce head formation.

  • Lettuce leaves start to form a cup shape and the head forms.
  • Every 6 to 8 weeks apply another application of PowerFeed Controlled Release for Tomatoes & Vegetables to produce a bumper crop.
  • Additional liquid feed plants with a combination of Seasol and PowerFeed every week. Mix 30mL of Seasol concentrate and 50mL of PowerFeedconcentrate per 9 litres of water (standard watering can).
  • Watch out for slugs and snails as they eat tender young leaves. Remove these little critters as you see them.

How to grow vegetables - lettuce

Step 7 – Lettuce harvest.

  • Keep a close eye on your plants and leaves. Either harvest the whole plant or just the leaves.
  • If harvesting the whole plant, cut at the base of the plant close to the soil.
  • If harvest the leaves, pick the leaves off the plant one level at a time, giving the inner leaves more time to develop.
  • Harvest the outer leaves when there is at least six leaves 100mm long. Don’t wait too long to harvest as bitterness can set in.
How to grow vegetables - beetroot

Things to watch out for.

  • Snails are the biggest pest for lettuces, with slugs and earwigs not far behind. For an organic treatment, try coffee grounds, broken eggshells or wood savings around the plants.
  • Aphids can quickly destroy a crop, as they suck all the water and nutrients out of the leaves. The leaves will curl and wilt. Remove by hand or spraying with an appropriate insecticide such as neem oil or pest oil,
  • If it’s too warm or leaves are left to long before harvest, the plant will bolt and go to seed. Check plants daily.