Growing Hydroponic Strawberries Indoors
We've been growing produce hydroponically in our home for a few years now and we decided it was time to try strawberries. Our two little girls eat strawberries by the handful so wouldn't it be cool to grow them 10 feet from our kitchen? In our climate in the midwestern United States, conventional outdoor strawberries have a very short harvest window - usually a few weeks in late June. On top of this, they are very prone to disease or pests - birds and bugs seem to like strawberries almost as much as our daughters. For us, growing strawberries outdoors would be challenging and could not provide a constant supply of strawberries through the colder months.
In theory, hydroponics could allow us to grow strawberries all year and alleviate the pest problem. We found some information online or from videos about growing hydroponic strawberries but the info was pretty sparse. We pieced together what we could find and made some modifications based on what we've learned from growing other crops hydroponically and the strawberry experiment turned out to be a success! We had some challenges along the way so here's what we've learned so far!
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The Hydroponic System
The first step is building the hydroponic system. We've been using DIY rail systems to grow lettuce, herbs and other greens, so we just added on to the rail system we already have. Strawberries seem to work well in a rail system since they maintain a fairly compact shape. We like rail systems because they are simple - all the plants can grow in one system instead of having separate pots or buckets for each plant. As an added bonus, we can grow strawberries in the same system as lettuce and herbs (more on that later). Also, since our rail system is modular, we can switch out rails without rebuilding the entire system. Check out our series on how to build a hydroponic rail system for more info.
We chose to use 2 inch net cups (Amazon) to give stability and room for the root base. For spacing, we drilled holes 8 inches apart along the rail (see the drawing below for full dimensions). Now that we're several months in, I would recommend spacing the plants closer to 10 inches since they fill out pretty nicely and the roots expand through the rail.
What we did: What we would recommend:
When choosing strawberry plants, it's important to find varieties that are everbearing (also called day-neutral). This means that the plant will have a continuous output of berries instead of putting all of its energy into one crop per year, which is what traditional June-bearing strawberries do. It's also important to buy strawberry plants and not just seeds, since it will take much longer for a seed grow into a mature plant and produce fruit. We went to a local greenhouse in the spring and bought bare-root strawberry plants for about $2 (USD) each. The only ever-bearing variety they sold was Monterey, which seems to be a good berry. Since the roots were fairly large when we bought them, we cut the bottom off of 2" net cups and packed hydroton around the bare roots to hold them in place.
In the winter months, we've ordered strawberry root stock from a nursery through Amazon and we've been very impressed with the plants.
As the plants grow they will send out runners. Unless you are looking to multiply your plants, go ahead and clip them off to direct the plant's energy towards leaves and berries.
Here's what our strawberry plants looked like a few weeks after planting:
Since we wanted to grow the strawberries in the same system as our lettuce and herbs, that meant we'd need a nutrient solution that would work for both. We started out with no change from our normal lettuce nutrients, but toward the end of our nutrient cycle we noticed the strawberry plants' leaf tips were turning brown and some of the leaves were yellowing - both signs of a nutrient problem. After some experimentation we determined that the nutrient levels were too high. With the way we manage nutrients, as the water would evaporate, nutrient density would increase (since the nutrients can't evaporate, only the water), and it was at this point that the strawberry plants started to suffer. It seems that lettuce is much more tolerant of a wide range of nutrients, but strawberries are a bit more sensitive. Keeping the nutrient levels below 800 ppm throughout the nutrient cycle fixed the problem and the plants took off. The strawberry plants have done well with the same Masterblend nutrients we use for lettuce (roughly 19-18-38 NPK).
We have been pleasantly surprised by the berry output from these plants! With 5 plants we've been picking between 25 and 50 medium-sized berries each week. Almost enough to keep up with our girls! The berries are very flavorful and extremely juicy. We're amazed that a fruit so bright red can come from a plant just growing in a clear nutrient solution!
The hardest part about harvesting is finding the berries - the plants grow quite dense so the berries can hide or they hang down off the rails. Our system is close to the ground so hard to get underneath, but if you are able to set your system up higher picking could be easier from underneath the plants.
Even indoors, bugs love strawberries. We made the mistake of taking our plants outside for a bit when we cleaned our hydroponic rail and soon after we had spider mites on our strawberry plants! We used AzaMax (same active ingredient as Neem Oil) to control them, but it's much easier to avoid them to begin with.
- Rail systems work well - space plants at least 8 inches apart
- Buy root stock of ever-bearing plants
- Keep nutrient levels between 600 and 800 ppm
- Watch for bugs
We hope you find this helpful! Be sure to check out our other articles on hydroponics and give hydroponics a try for yourself!