Spinacia oleracea (Chenopodiaceae or goosefoot family)
Production
Soil preparation
- Total nutrient uptake is 100 lbs. of N, 12 lbs. of P and 100 lbs. of K.
- Apply compost and other amendments based on the results of a soil test.
- Spread lime as needed to increase both the pH and Ca levels. Dolomite lime will also increase Mg levels. Spread gypsum when calcium levels are low but pH is correct.
- A fertilizer company can add OMRI-listed potassium sulfate to compost if it doesn’t have enough K to meet the crop’s needs. If this isn’t possible, spread the correct amount of fertilizer and incorporate it before planting.
- Incorporate compost and plant spinach in raised beds.
- Jang, Sutton Jr. or Planet Jr. planters in combination with small seeds like spinach don’t perform well with plant matter on the soil surface, so avoid planting them after tall green manures.
- Direct-seeded spinach requires a fine and firm seedbed. Prepare the land a few weeks in advance to provide the opportunity for some initial weed control via shallow cultivation or flaming.
- Alternatively, place a silage tarp over the prepared and irrigated seedbed 3–5 weeks in advance of the seeding date, depending on the time of year. This will flush many annual weed seeds and reduce weed pressure. Remove the tarp when the weeds have died.
Common recommended fertilizer rates1
| Nitrogen | Phosphorus | Potassium | pH |
| 125 | 0-170 | 0-200 | 6.5-6.7 |
| 1Rates are for New York and are from Cornell University’s Nutrient Guidelines for Commercial Vegetable Production (2019). Check the Cornell website for updated guidelines, or consult with local experts for recommended rates outside New York. | |||
Varieties
- Massachusetts overwintered spinach variety trial
- Washington State variety trial
- Some popular varieties are Space (disease resistant, good for all season), Equinox (for spring and fall), Kolibri (all season, good for baby size), Gazelle (for winter production) and Reflect (for heat resistance).
Direct seeding information
| Seeder | Rows | Seeds per foot | Seed plate no. | Depth (inches) | Sprocket setting | Notes |
| Planet Jr. | 3 | 50 | 20 | 2-4 | Mix with a biocontrol to avoid damping off. | |
| Sutton Jr. | 9 | 25 | 18 | 1/4-1/2 | 0.8 mph | |
| Jang | 5 | 24 | F24 | Front 14/rear 9 or 10 |
Transplanting and direct seeding tips
- You can transplant spinach using a paper-pot planter, which allows you to get optimum spacing and an early start. Start paper pots in the greenhouse. This results in a high germination rate. Use a pot spacing of 2 inches (CP303) for easy picking. Plant when the spinach has developed its first true leaves. Planting later leads to transplant shock. Don’t bury the plants, but make sure the pots themselves are covered to avoid drying out. Irrigate until roots are established.
- If damping off is an issue, add a biocontrol to the planter box. Trichoderma harzianum (as in T22) or Streptomyces iydicus (as in Actinovate or Micro 108) provide some efficacy.
Number of successions
- Start your earliest spring spinach in paper pots 7–10 days before you plant them in the field.
- When you transplant the paper pots, direct seed the next succession.
- For continuous harvest, plant another succession once the previous succession has developed its cotyledons. Stop seeding when the expected harvest date—which is 45–55 days from seeding—falls during summer heat. This is around mid-May in New York.
- Start planting spinach again when the expected harvest date falls at a time when the weather will cool off. This is around July 14 in New York.
Cultivation procedures
- Use a basket weeder or wheel hoe when weeds are in the white thread stage, without burying the young crop. Weed control is more effective when you eliminate weeds before they emerge.
- Hand weed as needed.
Frost, disease and insect protection
- For white rust, select resistant or tolerant varieties. Leaf miners can be a serious issue with spinach. Use row covers or insect netting to prevent the adult fly from laying its eggs on crops. If row covers or insect netting aren’t an option, place yellow sticky cards at plant height and check at least twice a week for adults that look like a fly, or look on the underside of the leaves for the presence of eggs. In the northern United States there are generally 3 generations of adult flies laying eggs. Once the eggs hatch ,or when you see the first signs of damage, apply a spinosyn-based product like Entrust every 5–7 days, not to exceed 3 sprays.
- To prevent deer damage, build a temporary fence using 4-foot fiberglass posts and attach 2 clearly visible wire like IntelliTape at about knee height. Build a second fence inside the first fence, but attach 2 wires or twine whereby the top line is about 7-feet tall. Deer don’t have very good depth perception and won’t attempt to jump this fence without checking out the first fence, so electrifying the second fence is often not needed. Bait the outside deer fence with peanut butter and electrify it. Make sure you build the fences, bait and electrify on the same day. The surprise effect is what matters most with this particulr deer control.
Other cultural practices
- Irrigate frequently for optimum yield and plant health. Frequency depends on soil type, evaporation, precipitation and the particular needs of the crop.
Double cropping and/or cover cropping
- Spinach rotates well either before or after other short-season vegetables like lettuce, mustard greens, arugula and radishes.
Additional resources
Harvest
| Yield | An average of 1 lb. per bed foot for baby spinach and an average of ¼ lbs. per row foot for full-grown spinach, because the rows are much farther apart. |
| Standards | Harvesting1 4–8 boxes per person, per hour, with each box containing about 8 lbs. The wide range is due to leaf size; baby spinach takes significantly longer to harvest than full-grown spinach. Machine harvest, using a piece of equipment mounted by a three-point hitch, can be up to 35–50 boxes per hour and takes 3 people. Field conditions have a big influence on the rate; you’ll need to slow down the machine dramatically for sorting for weeds, yellow leaves and leaf miner damage. |
| Washing 8–10 boxes per person, per hour | |
| Tools and supplies needed | A machine harvester or harvest knives, and regular 1 ⅓-bushel boxes |
| 1Harvest rates don't include the time required to transport crops from the field to a wash and pack shed or storage facility. | |
Ready-to-harvest and quality indicators
- Leaves are 4–6 inches tall, healthy and dark green.
- Spinach needs to be free of weeds, yellowing, necrosis or other blemishes. It can’t have signs of white mold, leaf miner damage or other pest damage.
Harvest procedures
- Wash your hands and sanitize knives before harvesting.
- Harvest in the morning hours to avoid field heat accumulation.
- Use different boxes for harvesting in the field and for distribution.
- Walk the fields before harvesting to inspect the crop for animal damage or feces. Mark these spots with a flag so the tractor operator or harvest crew can avoid harvesting near them.
- When machine harvested:
- Weed the field thoroughly before harvesting, as people on the machine won’t be able to keep up with sorting at the speed of harvesting.
- During harvest, remove all yellow leaves from the belt before they fall into the crates. When using a handheld harvester, you’ll sort after harvesting.
- When hand harvested with a knife:
- Hold a small bunch of leaves at the top of the plant with one hand and cut in one motion with the other hand.
- Remove any yellow leaves and stems from previous cuttings (if this isn’t the first cut).
- Place the leaves in a box.
Washing and storage procedures
- Wash hands and rinse boots before entering the wash-and-pack shed, and cover up field clothes with a bib. If a long-sleeve shirt contains soil, remove this as well.
- Add a sanitizer to the wash water. Use the guide How to Wash Produce Using a Peracetic Acid Solution to establish how much hydrogen peroxide and peracetic acid solution to add to water.
- Wash spinach at least twice, unless using a passthrough, conveyor-style washer (where water isn’t circulated).
- Don’t leave greens in water for longer than 1 minute. Leaves tend to get waterlogged after a few minutes, which causes them to deteriorate faster.
- Dry spinach in a centrifuge, but take care that leaves aren’t damaged, as this can cause bacterial soft rot (Erwinia and Pseudomonas) in storage. There are different sizes and models of commercial-grade salad spinners available through restaurant equipment suppliers.
- Pack according to the market:
- For wholesale, baby spinach goes in 5 oz., 10 oz. or 16 oz. clamshells
- For restaurants, full size spinach goes in in ½-bushel or 1 ⅑-bushel boxes
- For a CSA or farmers market, put baby spinach in clamshells and bag full-size spinach
Additional resources
Packing and storage summary for basil
| Cleaning in the field | Stems or yellow leaves are removed |
| Packing in the field | 8 lbs. per regular 1 ⅓-bushel box |
| Packing for delivery | 3 lbs. per regular ½-bushel box, or in 5, 10 or 16 oz. clamshells See the International Federation for Produce Standards for the correct PLU code. Add the prefix 9 for organic crops. |
| Storage | At 32°–42° and 95–98% humidity. Cover in closed containers or bags if stored for a few days. Spinach is highly sensitive to ethylene exposure, which will turn the leaves yellow. Allow for good air exchange and don’t store it with crops that release ethylene. |
This material is based upon work that is supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture through the Sustainable Agriculture Research and Education (SARE) program. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and should not be construed to represent any official USDA or U.S. Government determination or policy.