Lettuces all year round

Coloured lettuces
Photo: Penny Woodward

Anytime is a great time to plant lettuces. You just need to adjust what and where you plant, depending on the time of year. I love a good crisp hearting lettuce but lettuces aren’t just lettuces any more. They are red and yellow and spotted and bitter and sweet and curled and smooth. They are also fast growing and versatile. Grow them in pots and hanging baskets, use them to fill an empty spot as slower growing crops develop or grow them as a border in an ornamental garden bed. With the variety available you should never be without lettuce to add to your salads all year round.

Soil


Lettuces like a humus rich soil that is well drained. If you are planting in a pot use a really good potting mix, or a cheaper one to which you add some coir (coconut fibre) and compost at the ratio of 2:1:1. If you are planting in the ground you don’t need the coir unless the soil is very sandy, but you will need to add well-rotted manure and/or compost, half a barrow load to each square metre. Dig in well and smooth over the surface ready for planting either seed or seedlings. Lettuces do best in slightly acid soils with a pH of about 6.

Sowing and planting


Lettuces are annuals that grow easily from seed but you can also purchase seedlings. Sow seed in rows about 30cm apart, and cover with only a very thin layer of fine soil. Water gently and keep moist until the plants are well established. Most lettuce seed will not germinate once temperatures reach 30°C, optimum germination is 10°- 20°C so in the middle of summer, sow into trays or pots in a cooler positon. When the seedlings are a few centimetres high you can start thinning to about 25cm between plants. Eat or replant the thinnings. If you grow or purchase seedlings, make sure they are new and young, don’t purchase a tired old punnet with over-grown plants as they may just go straight to seed after planting. Always plant seedlings in the cool of the day, and if possible shade plants for the first few days until established.


Growing


Lettuce likes sun for about half the day in summer, preferably morning sun. Most lettuces dislike really hot conditions, especially when it is combined with high humidity. So at this time of year seek out a shadier position.  On the east side of taller vegies like sweet corn works well. Mulch the soil with pea or lucerne straw or sugar cane mulch to make sure that lettuces never dry out, or the leaves may be bitter. Water with seaweed emulsion and fish emulsion or weed tea or worm juice or liquid compost every couple of weeks. In warm humid regions don’t over water as this can cause rotting and wilting.
Bolting
The term bolting describes what a plant does when it starts to produce flower heads and go to seed, usually before we want it to. With lettuces and other leafy salad plants, it is the leaf we want to use.  So we grow types that are slow to bolt.
Harvesting
From seed to first harvest is about 25-30 days for mini and looseleaf types. These non-hearting types of lettuce can be harvested as soon as they have a few large leaves. Once any lettuce starts producing a flower head, the leaves become progressively more bitter.

Pests and diseases


Lettuces are relatively pest free. Young plants will need protection from snails and slugs, and from being scratched out by birds. If they are affected by aphids then spray with soap spray.

Some lettuce cultivars
Leafy lettuces to plant in summer


These cultivars are some of the most heat tolerant and the easiest to grow in summer. They grow as an open clump of leaves and don’t form a head. Harvest over a long period, pick individual leaves whenever needed, this is known as ‘cut and come again’. Sow at any time of the year.


Open-hearted cultivars

'Australian Yellow Leaf’ crisp leaves, decorative


‘Buttercrunch’ butterhead type with soft, ruffled leaves, creamy in the centre and dark green on the outside. Grow in a shadier position. Usually harvest whole head.


‘Flame’ deep red buttery leaves
‘Goldrush’ golden crinkled leaves, very slow to bolt.


‘Green Coral’ and ‘Red Coral’ deeply divided with bright green or red leaves.


‘Green Mignonette’ butterhead type with tender and sweet, deep green frilled leaves. Grow in a shadier position. Usually harvest whole head.


‘Lollo Rossa’ frilly, red tinged leaves, heat tolerant and very decorative.


‘Royal Oakleaf’ very decorative with bright green, deeply lobed leaves, also a purple form. Leaves don’t get bitter even in really hot weather.


‘Salad Bowl Red’  and ‘Salad Bowl Green’ long, lobed leaves, either burgundy or green. Good in the tropics, very decorative.

Cos or Romaine cultivars


These lettuces have crisp, juicy, sweet leaves. Very hardy and bolt resistant. Can harvest outside leaves over a long period, or the whole lettuce.

‘Crispmint’ very upright, green crisp leaves


‘Forellenschuss’ or ‘Freckles’ deep green glossy leaves with red splashes. Heat-tolerant heirloom


‘Little Gem’ mini cos type with crisp leaves, cream on inside, dark green outside. Heat tolerant.


‘Paris Island Cos’ upright, dark green outer leaves, cream in centre. Good in the heat.


‘Rough d’Hiver or ‘Brown Romaine’ burgundy edged dark green leaves, upright but non hearting, heat resistant.

By: Penny Woodward

First published: December 2021

Related topics

Plants & Vegetables, All Gardens, lettuce, bolting, open-hearted, cos, romaine, Buttercrunch, Flame, Goldrush, Green Coral, Lollo Rossa, Royal Oakleaf, Crispmint, Rouge d'Hiver, What to plant now
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