Asparagus is a well-known addition to many meals, especially around spring and summer. The green vegetable is rich in vitamin C, vitamin B, iron, and calcium, and is well known for its health benefits. It’s also one of the first crops to get harvested at the start of spring. Like many other vegetables, growing asparagus in your home might seem like a daunting task to undertake. But our guide details everything you need to know about how to grow asparagus indoors.
Stages Of Asparagus Growth
Before we get into how to grow asparagus, it’s important understand the stages of growth it goes through. Asparagus is slightly different than many other plants, and it forces us to adjust our expectations a bit.
First off, asparagus is typically not harvested until its third year of growth. This helps it build up a store of energy, and allows it to continue to grow back each year. Harvesting too soon can greatly reduce the life expectancy of your plant. Properly cared for, it will grow back each year with fresh spears to harvest.
That leads us to the first stage, the spear stage. This is when your plant is harvestable, and typically lasts about 2 months. During this period you’ll see rapid spear growth, and be able to harvest almost daily. We’ll talk a bit more about this later.
Afterwards, your asparagus will grow much taller and begin to flower, this is the fern stage. This is important to help your plant store energy for the winter. During this time, don’t cut back these large ferns as they are necessary for future growth. This stage will last until the winter when the plant will die back.
Lastly, we get the winter dormancy stage. In this stage your asparagus will survive, but below the ground. Many plants go through winter dormancy, and it is a key part of their growth cycle. This is important period for your plant to prepare for the coming growing season in spring.
All 3 stages are important, and understand them is key to getting a successful harvest year after year.
Different Kinds of Asparagus You Can Grow
Before you jump into planting asparagus in your home garden, you need to be aware of the different types of asparagus.
First of all, the plant can either be male or female. The significant difference between the two is that the latter produces berries while the former doesn’t. As the male plants conserve more energy, they’re three times more productive than their counterparts and produce larger crops. For maximum harvests, choose male varieties.
Moreover, there are different types of asparagus, but green asparagus is the one most commonly found in supermarkets. Other types include the white asparagus, purple asparagus, and jersey series asparagus, which includes categories such as Jersey knight, Jersey King, and Apollo.
Overall, you’ll find almost fifteen different variations of asparagus. Depending on what you want to grow, you’ll have to adjust your harvesting and planting process accordingly. Much of the care is the same however, so you can follow this guide regardless of the variety you choose to grow.
Soil and Container
Starting with quality soil is a must for proper asparagus growth. In containers, most commercial potting soils will work well. You can also go with vegetable specific mixes to get a bit more nutrients.
If grown outdoors, look for an area that is well draining and has a PH in the range of about 6.5 to 7.0. Well draining soil is a must, don’t plant in an area that frequently gets waterlogged or has sitting surface water.
Asparagus needs a lot of room to grow, so you’ll need to select a container that can accommodate it. Look for one that is at least 12” deep and is 3-6 feet in length. This should provide ample space for the plant to grow. Outdoors, you’ll want to choose a plot of similar size or larger to grow your crop.
Sunlight and Location
Asparagus are high light plants and need a bright, sunny spot in order to thrive. The ideal location for planting asparagus would require at least 6 – 8 hours of direct sunlight daily, but a bit more won’t hurt. Shady locations getting less than this will lead to small crops and slower growth.
If you’re having trouble hitting this, getting a good grow light would be a smart idea. Make sure to run this for longer than natural light. For example, if you’re solely growing by grow light you’d need to hit 12-14 hours of light. Also, make sure your plant is getting evenly lit which may require moving your lights every few hours.
Asparagus is generally grown from crowns, but you can also grow from seeds. We’ll take a brief look at both.
For crowns, start by digging a trench that is about 6-8” and at least a foot wide/long. When growing in a container, this trench should be about the size of the container. If you’re digging more than one trench outdoors, they should be at least 3 feet apart to give individual plants room to grow. You can now place your crowns in the trench, but be sure to soak them in warm water for about an hour beforehand and plant them about a foot apart. .
At this point, you have two methods for covering your trench, the all at once or little by little methods. All at once is simply that, you fill in the trench completely covering the crown.
The little by little method will have you start by covering the crowns with about 2” of soil. Then, once the asparagus spears have poked out a few inches, add another 1-2” of soil to almost cover the spears again. Repeat this process multiple times until you harvest.
Many gardeners will swear by the little by little method, claiming that it leads to healthier, stronger crops. Others will say it makes no difference. In our experience, both methods can work, and which one you choose will depend on the amount of time you can invest in your crop.
When growing from seeds, you’ll want to start with a similarly sized space. Plant the seeds to the depth recommended on the seed packet, don’t worry about spacing too much at this point. Once you see seedlings, you can go back and space out to give about 6-10” of space between each one.
Asparagus likes to grow in moist but not overly wet soil. Too much water can lead to issues like root rot, which can kill your plant.
You should water when the top inch of the soil is dry, and the soil at about 3-4” is still slightly moist. Give the plant a good dose of water that thoroughly soaks the soil. You’ll generally need to water a bit more in the early stages of development, but will tend to water less as the plant matures.
Look to fertilize your plants throughout their growing season, generally once per month starting in spring. It’s also a good idea to do so after a harvest to replenish the soil and encourage more growth.
Asparagus can be grown in multiple regions, but you’ll find the plant at its best in areas with long winters. Usually, the vegetable is planted right around early spring, the same time as potatoes. Asparagus spears generally start appearing once the soil reaches 50°F. You can also start seeds indoors a few weeks earlier and move them outdoors once you’ve past the last frost date. Asparagus does quite well in most temperatures, as long as it’s protected from frost and freezing conditions.
When harvesting asparagus, it’s best to wait until its third year before doing so. If asparagus is harvested too early, the plant does not have enough time to grow and spread its roots which will weaken it in subsequent years. If you wait, your asparagus will be able to come back and be harvested the following years, while asparagus harvested too soon is likely not to do so.
When you get to harvest time, it’s important to check your asparagus spears daily. Asparagus grows quite quickly, and waiting too long will lead to tough, inedible vegetables. Asparagus spears are ready to harvest once they’ve reached about 8-10”, and should be immediately harvested once they reach that size.
To harvest, simply take a sharp knife and cut them at surface level. Be careful not to disturb the ferns until they have died back in early winter. Harvesting in this manner will ensure that your asparagus continues to grow, and you’ll likely be able to harvest multiple times in the same year.
After a harvest, give your asparagus a dose of fertilizer to encourage further growth.
You should generally avoid replanting asparagus. That’s because there’s a high chance that you might end up disturbing the roots which can cause permanent damage to the plant. This warning goes for mature plants, transplanting seedlings is easy and acceptable.
The ideal time for transplanting is early spring. That’s when the plant is usually in its dormant state and easiest to move. You’ll have to be careful while digging out the spears. Once you’ve resettled the spears, water them and monitor them to see any changes.
Try to avoid harvesting the spears again for a year afterwards to allow the asparagus bed to resettle.
How To Grow Asparagus Indoors
Asparagus can be a tricky plant to grow and can take years of patience. Those that are willing to do so, however, will be well rewarded. Asparagus can continue to grow for decades, so some hard work now can pay off in spades for years to come. Don’t be turned off by this plant, it’s well worth the time to have a flourishing vegetable garden for years to come.
How far apart Should I Plant Asparagus Crowns?
You should ensure that the asparagus crowns are at least twelve to fourteen inches apart in a row. This distance gives asparagus the room it needs to grow.
Why Shouldn’t I Harvest Asparagus in the First Few Years?
Not immediately harvesting the asparagus plants will allow them to be more productive throughout their life, and lead to a crop that is able to survive year to year. When harvesting too early, you stress the plant and can lead to one that is unproductive in the following years.
How Long Do Asparagus Take To Grow?
After the initial waiting period, asparagus grows quite fast. It’s not uncommon to get several harvest per season out of a single crown.
How Long Do Asparagus Plants Last For?
Asparagus come back each year, and with proper care have been know to survive for up to 15-20 years. Indoors you can expect significantly less, but can still get 5-10 years out of a single crop with consistent, proper care.