Growing Spinach In Greenhouse – In Winter, Indoors From Seed, Polyhouse

Growing Spinach in Greenhouse

Hello gardeners, we are here with a new and interesting topic called growing spinach in Greenhouse. Do you want to know how to grow spinach in a greenhouse? Well, this article may help you to know about growing spinach in a greenhouse. In this article, we also discuss all the related topics and all requirements for growing spinach in Greenhouse or controlled environment.

Introduction to Growing Spinach in Greenhouse

Spinach is one of the first short-season plants, cold-tolerant salad greens to point out within the home kitchen garden. It’s an easy-to-grow green that’s rich in nutrients. It doesn’t need much space and additional care to grow. Spinach is one of the common leafy vegetables that are grown worldwide for its high nutritious value. Spinach belongs to the family of Amaranthaceae, and the scientific name of spinach is Spinacia oleracea. Spinach is one of the best vegetables that grow among the few vegetables with beets and chard that prefers a neutral to alkaline soil pH level 7.0 or above

A Step By Step Guide for Growing Spinach in Greenhouse

Guide for Growing Spinach in Greenhouse
Guide for Growing Spinach in Greenhouse (Image credit: pixabay)

Spinach is a very traditional greenhouse product. It is an annual plant that belongs to the amaranth family. Several gardeners are growing them for many centuries. The core of success will start with preparing them off from day one. It may be cut many times in a period and give steady off-season revenue.

Benefits of Growing Spinach in Greenhouse

Spinach leaves are used as a vegetable and they are a great source of Vitamins A, B, and C and they have the highest concentration of iron and calcium of all green vegetables. Spinach may increase your brainpower; however, it can also limit iron absorption.

Varieties/Types for growing Spinach in Greenhouse

Spinach mainly comes in three types:

  • Savoy

Savoy spinach has crinkly leaves and grows closer to the bottom than other types, so it’s more likely to urge splashed by mud and is harder to wash than smooth-leaf types. It’s also more cold-tolerant and disease-resistant, with an almost chewy texture because of thicker leaves.

  • Smooth leaf

The flat, smooth leaf spinach varieties are most common in Western states. As mentioned above, their smooth texture will make for faster cleaning after harvest. They can also extra tender.

  • Semi-savoy

Semi-savoy types are a pleasant compromise, with more upright plants and fewer crinkly leaves than savoy also nearly as good disease and bolt resistance in most varieties.

Seed Selection for Growing Spinach in Greenhouse

Good quality seed from a reputable supplier gives very predictable results. Seeds less than one-year-old generally have the best germination rate. Older seeds have a germination rate of less than 80 percent and they take longer to sprout out. Seeds more than two years old will have such a low success rate that they are generally not worth planting.

Suitable Soil for Growing Spinach in Greenhouse

In case if you miss this: Growing Parsley Hydroponically.

Soil for Growing Spinach in Greenhouse
Soil for Growing Spinach in Greenhouse (pic source: pixabay)

Spinach may be a veggie with beets and chard that favors a neutral to alkaline, well-drained nutrient-rich soil with pH ranging in between 6.5 to 7.0. Spinach may be a massive feeder. Begin by working two to four pounds of a complete fertilizer every 100 sq. ft. toward the soil then side-dress every fortnight or as required to stay them growing healthily.

Lighting Requirement for Growing Spinach in Greenhouse       

Spinach survives just as well in sunny and partial shade conditions. When looking to set up a greenhouse kit to grow your spinach, better ensure you place it for maximum lighting.

Seed Spacing or Plant Distance for Growing Spinach in Greenhouse

The final spacing of plants should be 4-6 inches apart since crowding can cause plants to grow poorly, bolt sooner, and devour diseases more easily in wet conditions. Some seed packets recommend 12 inches spacing, so check the directions for the seeds you select or choose.

Seed Germination for Growing Spinach in Greenhouse

Spinach seeds may germinate within 7 to 14 days at or near 21°C but sometimes seeds can take up nearly to 3 weeks to germinate in cold soil. When you’re sowing your spinach seeds in summer for fall harvest, then first you need to place the seed in a folded damp paper towel placed in a plastic bag and also keep it in the refrigerator for 5 days before sowing it.

Temperature Required For Spinach Seed Germination

Spinach seeds will germinate in 10°C – 22°C. Spinach germination will be very slow at temperatures that are near freezing, spinach seeds sprout out best at 15-20°C. 

How to Plant Spinach in Greenhouse?

  • Spinach does alright in well-drained nutrient-rich soil so you ought to till the soil a few weeks before planting and add aged manure
  • You can start the seeds directly in your garden or plant them during a nursery and transplant the seedlings about three weeks after they sprout
  • Sow the seeds in shallow holes between half an in. and one inch deep and canopy lightly. You ought to sow about 12 seeds per foot.
  • To increase germination, the well-liked temperature of the soil should be between 70°F and 75°F
  • You should avoid drastic temperature variations by monitoring spinach in your greenhouse
  • If you begin the seeds within the seedbed, thin them about three weeks after they sprout
  • Recommended spacing for growing spinach plants is 3 inches apart

Tips and Tricks for Thriving Spinach Plants

Spinach can tolerate weather or climate relatively well. However, young plants may have the protection of thick mulch in winter.

Spinach doesn’t require any special care. Even working the bottom round the roots makes no sense because its roots are shallow and any cultivation can easily damage them. Instead, apply mulch to suppress weeds and keep the soil moist.

Packed spinach plants may tend to remain damp for continued periods. This will be an issue with tons of diseases that bother the plants. It’s vital to stay them thinned and frequently weeded to take care of fresh air circulation through the leaves.

Mulching Spinach Plants in Greenhouse

You need to mulch well to keep the soil moist, as dry conditions may cause spinach to bolt sooner. Keeping the mulch from touching plants will prevent slug problems in your plant.

Water Requirement for Growing Spinach in Greenhouse

Spinach requires regular watering for good growth and development. Ideally, apply at least two inches of water per week. Make sure to water completely shortly after fertilizing your plant. You need to water adequately before and after the seeds germinate. They will not require any particular plant care aside from watering and harvesting.

Fertilizing Spinach in Greenhouse

Spinach is additionally an important feeder. Fertilize with a billboard food that contains much nitrogen or use an organic fish emulsion or cottonseed meal. Initially, incorporate fertilizer into the soil before planting. Then feed the spinach after it’s been thinned and again by side-dressing. You need to spread the fertilizer around the base of the plants and then gently work it into the soil. Take care; spinach has shallow roots that will be easily damaged.

Caring Tips for Growing Spinach in Greenhouse

The spinach plant will enjoy a healthy amount of sunlight. Overall, spinach doesn’t want any special attention to survive well. Proper fertilization, regular watering, and high nutrient-rich soil are all you want to ensure for a nice and better harvest.

Water spinach plants regularly when the top of the soil appears to be dry. as soggy soil may lead to many diseases and pest issues. Spinach plant prefers a high nutrient-rich soil, so better either uses a slow-releasing fertilizer or be prepared to feed often.

Spinach is a shallow-rooted plant and it wants consistent moisture to prevent bolting. Water the plants to maintain the soil always moist. Better mulch after plants is well established to maintain moisture and suppress weeds.

Do not over-fertilize the plant with nitrogen content. Only apply the supplemental fertilizer if plant leaves are in pale green. You can even add lime to make sure the pH level is at least 6.0. You should suspect that the soil is too acid if germination is poor and leaf tips and margins are yellow or brown.

Common Pests and Diseases in Growing Spinach In Greenhouse

Spinach is extremely vulnerable to leaf miner attacks. You can remove them with your fingers or sprinkle them with a garlic-soap spray.

Blue mold or false mildew and mosaic virus are even as catastrophic. Blue mold or false mildew is further managed by eliminating infected leaves. Search for yellow bits on the tip of the leaf and a grayish-blue mold on the underside or apply a prescribed fungicide.

Aphids are keen on spinach. But normally, a high-pressure water splash will knock them down otherwise you may plan to use one among the organic sprays available.

Caterpillars adore spinach, too. Apply one among the organic worm sprays to catch them without risk to pets, people, and helpful insects.

Anthracnose, Damping-off and Root rot, Downy mildew, and White rust all are the fungal diseases of the spinach plant.

Harvesting Spinach in Greenhouse

Spinach simply takes between 40 to 45 days to reach the complete harvesting period. Harvest spinach simply by plucking the leaves from the plant. If you want to develop full spinach leaves, make sure to harvest from the stalk, wash them, and tie in big, charming bunches.

Harvesting in the early morning is good because the leaves are at their most tasty after the cold moisture of the night. You can just pick bigger leaves by pinching or cutting the stalks near the bottom and leaving the shorter, inner leaves to size up. As quickly as they spring a flower stalk, you can cut the entire plant off at an end an inch over the base and then uproot and compost all the bulbs. Never wait for too long before harvesting, or never expect bigger leaves because bitterness will set in soon after their maturity.

Commonly Asked Questions about Growing Spinach in Greenhouse

How long will it take to germinate spinach seeds?

It takes nearly 5 days to germinate spinach seeds.

The primed seeds will retain enough moisture to finish the primary two stages of germination. After planting, primed spinach seeds germinate in just 5 days, compared to 10 or more for seeds straight out of the packet.

Why my spinach seeds are not germinating?

When you have planted in the right soil, spinach seeds will germinate very fastly and quickly. It only takes nearly about 5-10 days for the seedlings to start emerging. If the soil is too warm or too wet, it may inhibit the germination process. So, if your spinach seeds are not growing, then the soil could be too warm or soggy for them.

Will spinach grow back even after cutting?

As long because the growing point isn’t damaged during the initial harvesting and therefore the weather remains cool, spinach plants will presumably regrow for 2 or more harvests. The leaves should then regenerate for a second harvest within four weeks after the primary cutting.

Why my spinach seedlings are dying?

Damping-off of spinach seedlings is often caused by Pythium disease; this is a family of fungus made up of several species that all have more or less the same effect. Other pathogens diseases, including Rhizoctonia, Fusarium, and Phytophthora, May also cause spinach damping-off and seedling blight. This is the main reason.

How many times can I harvest spinach?

Harvest your spinach when leaves reach the desired size. You should not wait too long to harvest or wait for larger leaves; bitterness will set in quickly after the maturity of leaves. The whole spinach plant can be harvested at once and need to cut at the base, or leaves can be picked off plants one layer at a time, by giving inner layers more time to develop.


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