Organic Lettuce Seeds::Organic Green Romaine Lettuce::Organic Green Towers Lettuce
Organic Romaine Cos Lettuce Comparison Chart
||DM (1, 4-21, 23-26) MTO-30
||mini head, dark and glossy leaves, smooth and dense, blanched hearts
||requires cool temperatures to germinate, heads average 9-10", heads are tightly and rounded, sit high on stem, nice texture and flavor
||bright green with crimson splashes, upright, early color, crisp, good at any size
||Parris Island Cos
||uniform, grey-green heads, 8-12" tall, slightly savored
||DM (1-23,25) MTO-30
||midi heads, dark green, relatively smooth
||bright green, silky texture and sweet flavor, good for field and hoop house
||industry standard, very reliable, widely-adapted, uniform, 10-12" tall
||dark green, tall, sturdy heads, firm ribs, great for hearts or box packing
||DM (1-16,19, 21, 23)
||dark green, round and wide leaf
Downy Mildew (race specified if known)
Lettuce Drop, White Mold, Sclerotinia
Lettuce Mosaic Virus
indicated that 0 seeds out of 10,000 or 30,000 seeds have tested positive, respecively (aphid resistant varieties are bred to reduce the spead of LMV from other crops or non-resistant varieties)
Organic Lettuce - Growing and Seed Saving InfoPrintable version of this page
| Lettuce |
| Lettuce (Latuca sativa) is cool season annual in the Compositae family, which includes endive, escarole, chicory, globe artichoke, sunflower, Jerusalem artichoke, salsify, and burdock. |
- Looseleaf- var.crispa. First to maturity, these fast growing lettuces do not form a head. Good for babyleaf culture.
- Butterhead - also known as bib, or Boston, this type forms a loose head with slightly oily leaves. Beautiful, sweet and tender, but bruises and tears easily.
- Romaine var.longfolia. Romaine forms a tall dense upright head with a tender heart. It tolerates warm temperatures and is less prone to bolting.
- Iceberg var. capitata. The fussiest type to grow, iceberg will form a compact round head if given a long cool season. It bolts easily if stressed.
| Soil Requirements |
| Choose cool, well drained, loose soil with pH 6.2-6.8. Lettuce is sensitive to low pH. Use 50-75lbs Nitrogen/acre, ~150 Phosphorus and Potassium/acre. Sidedress with N 3-4 weeks after planting. With transplanting, use 2lbs/50 gallons starter fertilizer, 4-8oz per plant. |
| Position |
| Full sun to partial shade |
| Seeding Depth |
| 1/8, seeds require minimum amount of light for germination. |
| Seeding Rate |
| Babyleaf - ~60 seeds/ft, in 2 bands. Full size - ~3 seeds every 8-10. |
| Plant Spacing |
| Babyleaf continuous band. Full size 8-12 |
| Row Spacing |
| Babyleaf - Ύ between bands, 16 rows/36 bed. Full size - 12-18 or 3 rows/36 bed, 5 centers. |
| When to Sow |
| Lettuce can be seeded in the spring as soon as the soil can be worked. Days to maturity are from direct seeding in spring conditions, subtract 10-14 days if transplanting, subtract 7-10 days if planting in summer conditions, add 20 days if planting late summer-fall In certain areas, lettuce can be grown throughout the summer by choosing varieties which are heat tolerant; however, many lettuce varieties have difficulty germinating in soils above 75°F. Start transplants 3-4 weeks before setting out. Sow seeds 4 per inch in flats or small-cell plug trays, barely covering with fine soil. If sowing into flats, transplant 2 weeks later into plug trays, pots, or into another flat at 1-2 apart. |
| Other Considerations |
| Harden off seedlings by reducing water and temperature for 2-3 days before transplanting. |
| Frost Tolerant |
| Choose cold tolerant varieties to withstand light late-season frosts. |
| Drought Tolerant |
| Keep moisture levels even. Drought stress can cause bolting. |
| Heat Tolerant |
| Choose heat tolerant, bold-resistant varieties (such as Batavian types) for summer plantings. |
| Seed Specs |
| 24,000 seeds/oz avg. M= 1,000, MM=1,000,000 |
| Seeding Rate |
| Baby Leaf - 96M seeds/100 bed (~ 4 oz), 960M seeds/1,000 bed (2.5 lbs), 7.7MM seeds/acre (~20 lbs), using ~960 seeds/ft, 16 rows/bed, 36 beds, 6 row centers. Full Size - 360 plants/100 beds (~1/32 oz), 3,600 plants/1,000 beds (1 oz), using 10 spacing, 3 rows/36 bed, 5 center beds. 31M plants/acre (~2 oz), using 10 plant spacing. These specifications are meant to be general guidelines for the particular application as noted. They can be loosely applied across the board for lettuces/mixes found in this section. |
| Seed Coating / Pelleting Info |
| Some of the varieties we carry receive an organic film coating applied to the seed, which make the seed easier to see during planting. |
| Harvest |
| Cut lettuce holds best when harvested in the morning and cooled rapidly. For salad mix or baby leaf production, harvest individual leaves when they reach desired size, or cut evenly across the bed making sure to stay above the growing tip. For a continuous harvest, sow lettuce every 3 weeks. |
| Storage |
| Store just above freezing temperatures with 98% humidity. |
| Pest Info |
- Tarnished Plant Bugs cause brown scarring on stems. Romaine is especially susceptible.
- Cabbage looper and cutworms can be controlled by Bacillus thuringiensis (such as Dipel DF, see Supplies) and/or spinosad (such as Entrust), preferentially in rotation with one another to prevent selection of resistant individuals (check with your certifier before applying).
- Leafminers burrow underneath the skin and leave weaving, translucent trails. They are usually controlled by natural enemies.
- Slugs and Snails can be baited by beer traps. Practice clean cultivation and avoid mulch.
| Disease Info |
| Many lettuce diseases are best prevented by production practices that maximize airflow around heads to stimulate rapid drying. Many varieties have been bred to have disease resistance. |
DM: Downy Mildew (race specified, if known), TB: Tip Burn, WM: White Mold, BHR: Bacterial Head Rot, BR: Bottom Rot, HS: Heat Stress, LMV: Lettuce Mosaic Virus, APH: Aphids,
- Drop (Sclerotinia sclerotiorum, also called white mold). Grow on raised beds, rotate crops with grass.
- Bottom rot (Rhizoctonia solani). Select plants with upright growth habit. Take care not to set seedlings too deep.
- Lettuce mosaic virus (LMV) is highly seed-borne. Choose a reputable seed source. MTO-10, MTO-30: 10,000 or 30,000 seeds were tested for the presence of Lettuce Mosaic Virus, none was found. A disease-free test does not guarantee a seed lot to be disease-free, only that no pathogen was detected in sample.
- Damping-off (caused by a number of soil-borne fungi) Avoid overwatering when plants are young.
- Downy mildew (Bremia lactucae)
| Seed Saving Instructions |
| Self-pollinated. Lettuce varieties will not cross pollinate with each other even at short distances, but beware of any wild lettuce which can cross with lettuce. Allow plants to "bolt" and eventually flower. Under wet conditions lettuce plants may need to be covered with a rain cover or grown in a greenhouse to prevent fungus from infecting the plant and seed heads. Carefully shake the seedheads into a paper bag to allow the mature seeds to be collected while leaving the immature seeds and flowers to keep growing. Gather every few days until no more seeds remain. Also, you can simply harvest the entire plant when about half of the seeds are mature and allow the rest to mature inside by standing up the plants in a box and on a cloth or tarp. Use an 1/8" screen to help with cleaning. Lettuce seed can remain viable for 3 years under cool and dry storage conditions. |