When you’ve got the winter blues and are eager to get something green started in your garden, growing spinach might be the season extender you’ve been looking for. As one of the earliest plants to be ready in the springtime, spinach is full of the vitamins and nutrients that your body will be craving after a long winter without freshly grown produce.
As a satisfying cool-weather crop, spinach grows large yields of antioxidant-rich leaves in chilly conditions, but be warned; even the hint of temperatures above 80 degrees will be enough to end your spinach crop.
The secret to success with growing spinach is to get it in the ground early as early as you can. Once you plant your spinach, you’ll be well ahead of the seasonal growing game. And, you will be enjoying delicious spinach salads while the rest of your gardening friends are waiting for the weather to warm up enough to sprout their tomatoes.
Start Growing Spinach
Because spinach grows so early in the season, it’s easiest to simply direct sow your seeds when conditions are right. After the soil is workable, you can plant a few seeds every week. That way you can stagger your harvest and extend your spinach season. However, an alternative is to purchase transplants from plant nurseries. This will allow you to plant when it’s slightly too late in the season.
When and Where Should You Grow Spinach?
Spinach is a fast-growing plant that will produce harvest-sized leaves before other garden crops have even germinated, meaning you can get a good harvest both in the spring and fall. Though spinach needs full sun to grow optimally, the trick is to keep the leaves cool enough that they don’t overheat and bolt before you’re ready to give it up.
Understanding Seed Germination for Spinach
Spinach seeds can vary extensively in how long they will last. Some varieties will only last a year or two while others can make it for five years before their germination rate is affected, so read up on your varieties and store your seeds carefully for the best results. If you have problems getting your seeds to grow, their age is the likely cause, so buy some new ones and start over.
When the weather is chilly but not freezing, spinach seeds will germinate within a week of being planted.
Preparing a Spinach Bed
Though it likes the cold, spinach is healthiest when grown in full sun and it prefers pH conditions where the soil is between 6.5-7.5. As a leafy green, spinach grows best when given plenty of moisture and nitrogen-rich compost. Animal-based sources of nitrogen like composted manure or blood meal tend to work best.
Because the plants form a deep taproot, you will want to till the garden bed deeply to make sure the soil is loose enough for the root to grow down as deep as they need.
No need to worry about the frost date, you can plant spinach outside as soon as the soil is workable, usually about eight weeks before the frost date (cold frames and high tunnels can be planted even earlier).
Sow your seeds half an inch deep and two inches apart in rows that are at least a foot apart. You can make successive plantings every ten days or so to ensure that you will always have spinach ready during its growing season. Once the seeds have sprouted at least four true leaves, thin them out until they’re spaced about six inches apart, which helps with overcrowding that can spread diseases from plant to plant. You can then enjoy the thinnings as the delectable ‘baby spinach’ treats they are.
Your crop will bolt by the time the temperature is consistently over 80 degrees, but you can get in a second crop in the early fall in colder regions. Also, if you plant seeds in October and protect the plants throughout the winter, you can have an extra-early spring harvest.
Growing Spinach in Containers
If you want to become a container gardener, spinach is a perfect candidate. You can grow it in tiny pots or shallow salad trays, so long as your plants get enough sunlight and water to stay happy. Simply plant your seeds a half inch deep into a container filled with a high-quality potting mix, and once the true leaves start to form, thin the plants out to three inches apart. This gives them the space to grow into tender baby greens. If the greens start to turn pale green, add extra nitrogen fertilizer to perk them back up.
When grown in pots that can be moved to cooler places when the temperature gets too hot, spinaches growth cycle can be considerably extended, allowing you to enjoy your spinach salads all summer long.
Watering and Mulching Requirements
When conditions are cool and sunny, spinach will grow without much help, but you can keep your plants in peak form by watering them regularly and deeply, about an inch a week. Hand pulling weeds near spinach often causes unwanted damage to the taproot, so a better strategy is to use a mulch of grass clipping or straw to suppress weeds instead.
Companion Planting and Rotation Considerations
Spinach is an easy crop that can be planted successfully with any garden plant. In fact, almost all crops (besides legumes) grow better after being planted in a bed that previously was used for spinach, making it a key crop to use in your rotational garden strategy.
Because spinach, lettuce, and brassicas like kale and broccoli all need the same soil conditions, they can be grown next to each other. A smart idea is to inter-plant spinach between larger crops like broccoli or cabbage because by the time the bigger plants need more space the spinach will be done for the season.
Common Pests and Diseases for Spinach
Because spinach grows so early in the year it tends to be done for the season before the worst pests and diseases become a problem. However, there are a few regular issues that most spinach growers will have to face.
- Leafminers: These tiny flies lay their eggs on the underside of brassicas like spinach, beets, and chard and the hatched larva loves to burrow in the leaves and create tan, tasteless patches. You can protect your crop by pulling off infected leaves or covering your beds with row cover.
- Flea Beetles: Equally tiny, flea beetles come out early in the growing season and like to chew small holes in spinach leaves, weakening them until they shrivel. If you get an infestation, row cover is the best defense, or possibly planting something that they love to eat even more (such as eggplant) to distract them from your spinach.
- Spinach blight: This fungus is spread by aphids and will turn spinach leaves yellow and stunt them. Keeping ladybugs around your garden as a natural aphid predator can help keep these pests in check, as can planting disease-resistant varieties like ‘Indian Summer’ or waiting until your plants are completely dry before touching them to stop the spread of fungus spores.
Harvesting and Storing Spinach
Six to eight weeks after being planted, spinach should be ready for harvesting, though the leaves can really be harvested at any size. You can harvest the leaves either by carefully cutting off the outer leaves or by cutting off the entire crop about an inch from the soil. Though you’ll get a more consistent harvest from selectively cutting the outer leaves, harvesting the entire plant triggers it to grow back quickly, meaning you can get several complete cuttings off each plant. Be sure to harvest any plant that looks ready to bolt, as the leaves will become bitter as the plant ages.
After being harvested, spinach leaves should be rinsed in cold water, spun until dry and stored for up to a week in the fridge. You can also dry the leaves in a dehydrator or blanch and freeze them.
Saving Spinach Seeds
Because spinach will cross-pollinate with other varieties, you will need to isolate your seed crop with row cover to prevent it from getting contaminated. Allow these plants to bolt and set seed, staking the plant upright if it looks like the height is getting too precarious. Once the seeds are dry, harvest the entire plant and thrash it against a tarp, sorting out the seeds in the process. When stored in a cool, dry place these seeds should last for several years.
Choosing the Best Spinach Seeds for Your Climate
The type of spinach you choose to grow will depend on your climate conditions and the time of year that you want to get a harvest. Some varieties do better with freezing temperatures than others, like ‘Bloomsdale‘ or ‘Regiment‘, which will continue to grow after a major cold snap.
For the summertime, bolt-resistant varieties like ‘Tyee‘, ‘Bloomsdale Long Standing‘ or ‘Space‘ will last the longest, especially if planted in the partial shade. For extra success during germination, be sure to plant these seeds down deeply (about an inch) so that they don’t get too warm.
Additional Growing Tips for Organic Spinach
For the best chance of success with your spinach crop, follow the tips below.
- To improve the often poor germination rate of spinach seeds, soak them in a compost tea solution for twenty minutes before planting them. You can also place your seeds between a wet paper towel and put them in a bag, which is kept in the fridge for about a week.
- Cold frames can be used to regulate temperatures and get a spinach harvest throughout the winter.
- Consistently remove the largest leaves from your plants to prevent them from bolting prematurely.
- By planting summer spinach behind a tall crop like corn or pole beans, you can keep them shaded in the summer heat and get them to grow longer into the summer.