How to grow onions with the Paperpot Transplanter

Paperpot settings for onions

Use 6″ paper chain pots, drop 3 seeds per cell with the Kwik Klik Slide, and transplant 5 rows on a 30″ bed, 6″ apart. Plan on about 4 trays per 100′ bed.

Paper chain pot	6″
In-row spacing	6″
Rows per 30″ bed	5 (6″ apart)
Trays per 100′ bed	4
Kwik Klik top plate	Paperpot 264, 3 mm thick, 3 mm holes
Seeds per cell	3
Seed per 100′ bed	3,000 seeds (+/-)
Cultivars	Sierra Blanca (fresh), Red Carpet (storage)
Germination	72 hours at 80°F
Days to transplant	45 days
Days to maturity	110 days
Harvest window	14 days
Harvest unit	Pound
Yield per 100′ bed	350 lb

Bed figures are for a 100′ x 30″ bed. From the Paperpot Co. Growers Notes, developed with farmers Erich Schultz (Steadfast Farm) and Seth Davis. Adjust for your climate and conditions.

Bed preparation

• Broadfork the bed to aerate and loosen the soil.
• Smooth and shape the bed with a bed prep rake, removing any debris.
• Onions do best in a bed freshly amended. Layer on 1″ of compost (enough to mostly cover the native soil) or sprinkle on alfalfa meal and pelleted chicken manure.
• If you layer compost, don’t tilth it in, so surface weed seed stays smothered. If you add amendments, tilth the top 1-2″ to mix them in.
• Irrigate for 10 to 14 days* to germinate weed seed in the top layer of soil, then flame weed once the weed cotyledons are up.

Seeding

• Set a germination tray with 6″ paper chain pots and fill with potting mix.
• Set up the Kwik Klik Slide with the Paperpot bottom plate and the Paperpot 264, 3 mm thick, 3 mm holes top plate.
• Pour seed on the top plate and work it until about 3 seeds sits in each hole. Line the seeder up over the tray and slide the plate to drop seed into every cell at once.
• Water the tray, then germinate for 72 hours at 80°F.
• Move trays to greenhouse benches as soon as you see germination.
• Trim 1″ off the tops at 4 weeks and again a week before transplanting.
• Starts are ready at about 7 weeks and 6″ tall. Plant storage onions once in spring; fresh onions can go in all season.

Transplanting

• Water the trays thoroughly before heading to the field.
• Plant five rows of onions with the Paperpot Transplanter: 6″ between rows, 3″ from the outer rows to the bed edge.
• New to the transplanter? See the how-to guide and videos.

Bed layout

Irrigation

• Water the bed in thoroughly with overhead irrigation or four lines of drip.
• Frequent, shallow waterings support fast growth and better flavor.

Cultivation

• 10-14 days after transplanting, cultivate with a collinear hoe or wire weeder.
• Keep at it: onions never close a canopy the way other tight crops do.
• Cover with insect netting if thrips or onion fly are a problem.

Harvest

• Fresh onions can be pulled with tops on and bunched in the field.
• Harvest storage onions when the tops start to die back, in dry weather.

Washing and packing

• Fresh onions: spray clean over a root wash table, pack in totes and store at 35°F.
• Storage onions: cure in a single layer on tables for 2-3 weeks, ideally with controlled airflow, temperature and humidity. When the necks are dry, cut the stems and store in mesh bags or boxes at about 46°F.

Onions in paper chain pots: FAQ

Other crops

basil · beets · bunching onions · cabbage · cilantro · dill · fennel · garlic · head lettuce · kohlrabi · leeks · Little Gem lettuce · mesclun mix lettuce · snap peas · salad turnips · spinach · storage radishes · summer crisp lettuce. All crops in one table: the Paperpot growers notes.