How to Grow Corn Salad (Lamb's Lettuce)

At a Glance

Quick Facts

Factor	Value
Soil pH	6 - 7
Time to harvest	14-21 days
Drainage	well-drained
Lifecycle	annual/biennial
Edible parts	leaves

Soil & Growing Conditions

Soil pH range

6 7

Span reflects genuine variation between the cited authorities, not a single agreed figure.

Growth Stages

Stage	BBCH	Notes
Sowing and germination	0	Sow about 0.5cm deep, normally late summer or autumn for a winter crop, or from a few weeks before the last spring frost; germinates in 5-14 days depending on soil temperature (RHS, Harvest to Table).
Thinning and rosette growth	1	Thin to about 10cm apart in rows 30cm apart; low rosette of soft, spoon-shaped leaves develops in sun or semi-shade, any well-drained soil (RHS).
Cut-and-come-again harvest	3	Pick outer leaves first once the rosette is established, leaving the centre to keep growing; protect with cloches in very harsh winter weather (RHS, Harvest to Table).
Bolting and flowering	6	If left uncut, tiny bluish or pinkish flowers appear in flat heads on multi-branched stems as the plant runs to seed (RHS).

Harvest & Storage

When to pick: Pull up alternate plants, then pick larger leaves as needed; best picked before flowering. Hardy into winter if not frozen.

Storage

perishable -- refrigerate promptly, e.g. with a slightly moist paper towel in a breathable bag

Diseases

Corn salad downy mildew

Peronospora valerianellae

Peer-reviewed APS Plant Disease report: Peronospora valerianellae confirmed causing downy mildew on commercial corn-salad plantings in California; crop loss 1-15%.

Pests

Aphids

Aphididae (various spp.)

Multiple horticultural sources note corn salad is susceptible to aphids as a generalist pest.

Sources

1. American Phytopathological Society (Plant Disease) - Downy Mildew Caused by Peronospora valerianellae on Corn-Salad (Valerianella locusta) in California
2. Harvest to Table - How to Grow Corn Salad (Mache)

   Sow seed 1/4in deep in rich, well-draining soil, starting 3-4 weeks before the last spring frost and again in autumn by early September; sow every 2 weeks for continual harvest. Germinates in 5-14 days depending on soil temperature. Thin to 4in apart in rows 12in apart (or sow direct 1in apart in rows 4-6in apart). Harvest begins 2-3 weeks after emergence/transplanting; pick outer leaves first, cut-and-come-again, letting centre leaves continue growing for multiple harvests through the season.

3. World Flora Online - World Flora Online: Valerianella locusta (L.) Laterr.

These 3 sources are specific to this region. The full list of 7 sources behind this guide (American Phytopathological Society (Plant Disease), Harvest to Table, Royal Horticultural Society and others) is in the references of our UK guide to corn salad (lamb's lettuce); they describe the plant itself, which is the same wherever it grows.