Spinach vs Lettuce: Leaves Growth plus Season
The spinach vs lettuce choice comes down to season plus leaf type. Both are cool season leafy crops. University of Illinois Extension notes spinach bolts quickly to seed during the long days of late spring, while lettuce thrives when the average daily temperature is 60 to 70 F. Lettuce comes in five distinct types.
The short answer
Spinach plus lettuce are both cool season leafy crops planted in spring or late summer. Spinach bolts quickly in the long days of late spring plus summer, so it suits early spring plus fall. Lettuce comes in leaf, romaine, butterhead, crisphead plus stem types. UF/IFAS places lettuce in the sunflower family, Asteraceae.
How do spinach and lettuce leaves differ?
University of Illinois Extension notes spinach comes in crinkled leaf types, which tend to catch soil during rain, plus plain leaf types. It lists five lettuce types: leaf, Cos or romaine, crisphead, butterhead plus stem. UF/IFAS notes romaine grows most upright with a crunchy midrib, butterhead has soft leaves plus crisphead forms a tight ball.
| Trait | Spinach | Lettuce |
|---|---|---|
| Leaf forms | Crinkled or plain leaves | Leaf, romaine, butterhead, crisphead plus stem |
| Ideal temperature | Grows well up to 75 F | Average 60 to 70 F daily |
| Spacing | 3 inches in rows 12 inches apart | 4 inches for leaf lettuce, 6 to 8 for Cos |
| Bolting trigger | Long days plus warm weather | High temperatures |
| Harvest | Leaves at full size, before the flower stalk | 4 to 6 weeks after planting in Florida |
Source: University of Illinois Extension, Utah State University Extension plus UF/IFAS Gardening Solutions.
Why does spinach bolt so fast?
University of Illinois Extension notes spinach bolts quickly to seed during the long days of late spring or summer, plus warm temperatures speed it up. Utah State University Extension notes spinach grows well when temperatures stay at or below 75 F. Long standing or slow bolting varieties are better adapted for late spring plantings.
Which grows better in spring and fall?
Both are spring plus fall crops. University of Illinois Extension notes spinach can be sown as soon as soil is prepared in spring plus again in late summer for fall. Utah State University Extension notes young spinach handles 32 F. University of Illinois Extension notes lettuce goes in early spring or late summer plus suffers in hot summer days.
How to: step by step
- Sow both as soon as the soil can be worked in spring.
- Sow spinach 1/2 inch deep plus lettuce 1/4 to 1/2 inch deep.
- Thin spinach to 3 inches plus leaf lettuce to 4 inches.
- Repeat sowings every 10 to 14 days for a steady supply.
- Pick slow bolting spinach for late spring sowings.
- Resow in late summer for a fall crop.
Troubleshooting
Spinach bolts early: long days plus warmth. University of Illinois Extension suggests long standing varieties for spring planting.
Gritty spinach leaves: crinkled leaves trap soil in rain. Grow a flat leaf variety.
Lettuce turns bitter: high temperatures. UF/IFAS suggests afternoon shade or shade cloth above 85 F.
For related reading see cannabis leaf anatomy, frost damage on cannabis plus raised beds for cannabis. Kind Seed Co also stocks cannabis seeds.
Sources
- Spinach, University of Illinois Extension
- Lettuce, University of Illinois Extension
- How to grow spinach in your garden, Utah State University Extension
- Lettuce, UF/IFAS Gardening Solutions
FAQ
Can spinach and lettuce be planted together?
Yes. Both are cool season crops. University of Illinois Extension notes spinach rows may be as close as 12 inches, while lettuce goes in rows 12 to 18 inches apart. Thin spinach to 2 to 4 inches plus leaf lettuce to 4 inches. Both can be sown early in spring plus again in late summer.
Which is more cold hardy?
Utah State University Extension notes temperatures down to 32 F do not seriously damage young spinach, plus spinach with 4 to 5 true leaves late in the year overwinters easily under heavy mulch. UF/IFAS notes lettuce tolerates light frost but suggests a frost blanket below 40 F. Spinach is the hardier of the two.
How do I stop spinach from bolting?
Plant early. University of Illinois Extension notes spinach bolts in the long days of late spring plus summer, plus warm temperatures speed it up. Choose long standing or slow bolting varieties for spring. Utah State University Extension suggests watering 1 to 2 inches per week so moisture swings do not slow leaf growth.
Can I grow both in containers?
UF/IFAS notes lettuce can be grown in the ground, in raised beds, in containers or in a floating hydroponic garden, with at least 10 hours of sun a day. University of Illinois Extension notes spinach can be grown in low tunnels, sunrooms or cold frames in winter. Raised beds give spinach good air plus water drainage.
How is spinach harvested?
Utah State University Extension notes single spinach leaves may be picked any time before the flower stalk forms. Older leaves are often stripped first so young leaves can grow. If the growing point is not damaged, all leaves can be cut to within 2 inches of the soil. Harvest leaves once they reach full size.
