How to grow lettuce
Lettuce is an easy to grow, staple leafy green that can be easily grown year round. You can grow lettuce quickly from seeds or seedlings, planted into a full sun to part shade spot. During the heat of summer it’s best to plant lettuce in a spot that gets protection from the hottest afternoon sun or beneath taller growing plants that will offer it some protection.
Lettuce needs a rich, free draining soil with regular watering during the warmer months. If left to dry out your lettuce will become bitter and possibly bolt to seed.
Lettuce comes in many different colours, shapes, sizes and even flavours. However there are 3 main types of lettuce;
- Crisp heading lettuce like Iceberg - These lettuce produce round or tightly formed heads. To harvest you remove the whole plant including its roots.
- Cos lettuces - A winter loving, elongated lettuce that does form a heart but can still have its outer leaves harvested leaf by leaf.
- Loose leaf lettuces like butterleaf or oakleaf - These lettuces don’t form a tight head and can be harvested leaf by leaf as needed. They are also some of the fastest growing lettuces.
Top 4 steps to growing lettuce
- Choose a full sun position or a spot protected from hot afternoon sun during the hottest months.
- Improve the soil before planting by adding compost or Scotts Osmocote® Compost Premium Soil Improver.
- Direct sow lettuce seeds into prepared soil or start them in Scotts Osmocote Seed & Cutting Potting Mix and transplant into prepared soil once they are big enough to handle.
- Lettuce is readily available as seedlings, plant a new punnet every 4-6 weeks to have a continuous supply of fresh lettuce to harvest.
- Slugs and snails are a big problem for lettuce crops. Sprinkle Defender Slug & Snail pellets around to keep your crops from attack.
- Lettuce seeds or seedlings
- Scotts Osmocote® Compost Premium Soil Improver
- Scotts Osmocote® Controlled Release Fertiliser: Tomato, Vegetable & Herb
- If growing from seeds, Scotts Osmocote Seed & Cutting Potting Mix and suitable small pots
- If growing in pots, Scotts Osmocote® Plus Organics Tomato, Vegetable & Herb Potting Mix and a suitable pot
- Garden trowel
- Defender Slug & Snail Pellets
Choose a full sun to part shade spot for your lettuce. During the warmest months of the year it’s best to grow lettuce in part shade or with protection from the hot afternoon sun. Lettuce can be planted beneath taller growing crops like tomatoes or corn for shade or you can set up a shade structure if needed.
Enriched the soil before planting lettuce with Scotts Performance Natural Soil Improver and a small amount of Scotts Performance Natural All Purpose Organic Based Fertiliser - dig these through the top 10-20cm of soil.
Growing from seeds
Lettuce seeds can be direct sown into prepared soil at any time of the year. Lightly sprinkle the seeds onto the soil surface and cover with 3mm of soil. Keep the soil moist until the seeds germinate. Once the seedlings are 5-10cm tall they can be thinned to the recommended spacing (check the instructions on the seed packet, as each variety will be slightly different).
Lettuce seeds can also be sown into punnets or small pots and transplanted into the garden once large enough. Fill clean punnets or small pots with Scotts Osmocote Seed & Cutting Potting Mix and sprinkle lettuce seeds onto the surface - cover them with 3mm of Scotts Osmocote Seed & Cutting Potting Mix and keep the potting mix moist until the seeds germinate. Once seedlings are 5-10cm tall they can be transplanted into your prepared garden soil or larger pots to grow on.
Planting in the garden
Lettuce can be grown in your garden year round - many varieties will happily grow in the coldest months of winter and survive frost. Plant lettuce seedlings into prepared soil at the recommended spacing for the variety you’ve chosen.
If direct sowing seeds into your garden follow the instructions under ‘Growing from seeds’ above.
Mulch around your lettuce plants to suppress weeds and retain moisture. Fertilise with a light sprinkle of Scotts Osmocote® Controlled Release Fertiliser: Tomato, Vegetable & Herb around each lettuce plant 6-8 weeks after planting.
Planting in pots
Lettuce can easily be grown in medium pots at least 20-30cm deep by the same width.
Fill the pot with Scotts Osmocote® Plus Organics Tomato, Vegetable & Herb Potting Mix and either direct sow seeds or plant seedlings. Position your pot in a full sun spot, but with some protection from hot afternoon sun during the warmest months.
Fertilise with a light sprinkle of Scotts Osmocote® Controlled Release Fertiliser: Tomato, Vegetable & Herb on the potting mix surface 6-8 weeks after planting.
Regular watering of lettuce is critical in pots, as small pots in particular can dry out quickly in summer. Mulch around lettuce plants to suppress weeds and retain moisture.
Loose leaf and cos style lettuces can be harvested leaf by leaf as you need them. Most of these are ready to begin harvesting about 6 weeks from planting. Don’t remove more than 50% of the leaf growth at any one time, so the plant can continue to thrive. Remove the outer leaves only and leave the inner ones to continue growing.
Hearting lettuces like iceberg are best picked when the heads are tight and round. Harvest by pulling up the whole plant, roots and all - they can take 12-14 weeks to reach maturity.
Pests & Diseases
Slugs and Snails will cause significant damage to lettuce at all stages of its growth. Protect your lettuce crop by setting beer traps (saucers filled with beer) or use Defender Slug & Snail Pellets.