How To Easily Grow Hydroponic Strawberries Indoors In A Tower Garden
Strawberries are a high-value crop that can be consumed fresh, added to yogurts, milkshakes, and ice creams, or used as a filling in pies and pastries. If you’re fond of strawberries, did you know that hydroponically growing them indoors is the best way to get the most of that juicy, sweet flavor?
Commercial growers of strawberries for grocery stores pick the fruits early to give them time to ripen during transportation. While this saves the fruits from being rotten by the time they are ready for sale, harvesting too early also significantly reduces the flavor!
In this article, we’re making it easier for you to learn how to grow strawberries from the comfort of your own home. In fact, you can grow them faster and save space at the same time by setting up your own hydroponic strawberry tower!
What is Hydroponics?
To new growers or even to long-time gardeners who are used to growing food in classic fashion, hydroponics might sound like an intimidating concept. If you’re willing to read through this blog post, however, you will soon learn that hydroponics makes gardening more hassle-free, less time-consuming, and more productive in terms of yield!
So what is hydroponics? Hydroponics is a horticultural method that eliminates the need for soil and instead provides nourishment to a plant’s roots through water and a liquid nutrient solution.
How Does Hydroponics Work?
In a hydroponic setup, plants are placed in net pots so their roots can grow through the holes and reach the water and nutrient reservoir right below. This method is known as Deep Water Culture (DWC), and is only one among many types of hydroponics.
A growing medium (such as clay pebbles, coco coir, or Rockwool) is placed inside the net cups to anchor the roots and hold the plants upright.
Water and hydroponic nutrients flow through a network of tubes in the system. A submersible water pump moves the water around and drains the reservoir when needed. Aeration stones and an air pump oxygenate the submerged roots.
Overall, the entire hydroponic system works to provide everything the plants need to grow in an indoor (or even an outdoor) environment, requiring little maintenance on the part of the gardener!
5 Benefits of Hydroponics
There are many benefits in choosing to grow strawberries and other crops hydroponically. Here are some of them:
- Higher yields: Hydroponic crops only need thin roots for water absorption, while their land-based counterparts take a lot of time developing thick and hardy roots. As a result, hydroponic strawberries mature and fruit at a faster rate. This increases overall strawberry production.
- Fewer pests: Most problems in gardening such as bugs, root rot, and fungal diseases thrive in soil. Hydroponics removes soil from the equation and reduces the risk for these diseases.
- Year-round harvest: Typically, strawberries are sensitive to temperature changes. You can only plant them outdoors in certain seasons of the year. Indoor hydroponics allows you to grow and harvest your own strawberries all year, as long as you choose ever-bearing varieties!
- Less water usage: Because most hydroponic systems efficiently recirculate the water, you end up conserving around 70% of water compared to land-based gardening.
- Less space: Built with a compact design, most hydroponic systems will barely take up space in your home. Vertical hydroponic strawberry systems are even more efficient, adding more plants without the need for more floor space.
Hydroponic Setups To Choose From
There are many types of good hydroponic systems to choose from depending on your level of expertise, your budget, and your growing goals.
- DIY mason jars can help beginners get started on growing food indoors. It’s a cheap and straight-forward set-up, but you’ll still need to provide your plants with a liquid nutrient solution and ample lighting next to a bright window.
- Countertop hydroponic systems come in many sizes and are perfect for those who like to grow food in their kitchen. To make the choice easier for you, we’ve written detailed reviews of products from brands such as iDOO, Click And Grow, AeroGarden, VegeBox, and many others.
- Vertical hydroponic systems are currently the most advanced in the market. They can set you back by hundreds of dollars, but they automate the growing process with LED lights and mobile apps. You can then harvest crops all year-round with little effort. They also take up very little floor space while providing the greatest yields out of all the systems.
- You can build your own DIY hydroponic tower garden with PVC pipes and wood frames which you can purchase from hardware stores. This is a great way to save money if you already have the tools and materials on hand.
Best Vertical Hydroponic Systems For Strawberries
According to a 2012 study that compared 4 types of hydroponic systems, vertical grow towers surpassed other systems in terms of fruit yield because they had the most number of plants per unit area.
Here are the 3 best vertical hydroponic systems for indoor strawberries:
- The Gardyn tower garden is the best invention of 2020 according to Time Magazine. It can grow 30 strawberry plants at a time within just 2 square feet of floor space. With fully-automated controls and sensors for the light output and water levels, you can do your gardening virtually from the Gardyn mobile app.
Its latest version, Gardyn 2.0, comes with a new energy-efficient pump and ultrasonic sensors to improve the accuracy of water usage.
- iHarvest is a hydroponic garden system that can yield up to $1,000 worth of fresh produce in a year. It can grow 30 strawberry plants at a time. It comes with LED lights, peat-based growing medium, Maxigro nutrient solution, and starter seed packets.
Aside from functionality, the iHarvest boasts a sleek, attractive design for your living room or kitchen.
- Aerospring as an indoor vertical strawberry planter can accommodate 27 plants at a time. It’s slightly different from other systems because it uses a more specific branch of hydroponics known as aeroponics. As a result, it can grow plants 3 times faster while using 98% less water than traditional gardening methods.
Aerospring comes with a detachable grow tent to improve the plants’ growth and to shield indoor inhabitants from the brightness of the LED lights.
8 Steps in Growing Strawberries Hydroponically
Now that you’ve picked your hydroponic system, you can grow your own strawberries indoors! Follow the steps we’ve laid out below:
Step 1 – Prepare your starter plant.
Strawberry seeds can be difficult to start. Even if you can get them to sprout, it will take a while for them to develop into full-sized plants. Instead, it’s a good idea to buy young strawberry seedlings from local greenhouses. In the colder seasons, you can order them online and they’ll be shipped to you as bare-root stocks.
When you receive the strawberry seedlings, wash the roots thoroughly to make sure you don’t bring any soil-borne pests to your indoor garden.
Step 2 – Choose a growing medium.
You will need a grow medium to hold the roots and keep the base of the plant steady. It will also block light from reaching the water in the rails (which leads to algae build-up).
Common options include: LECA (also called hydroton or clay pebbles), peat moss, gravel, vermiculite, coconut coir (also called coco peat or coco pith), and perlite.
Some systems such as the Gardyn, iHarvest and Aerospring come with specialized growing media made of sphagnum moss or basalt salt.
Tests in 2012 revealed that a potting mixture of perlite, cocopeat, and date-peat (made from palm tree wastes) increases the fruit yield, chlorophyll content, and leaf area of hydroponic strawberries.
Step 3 – Provide the correct growing environment for strawberries.
There are certain parameters that strawberry plants need in order to grow in an indoor setting. Here are some of them:
Light: Strawberry plants will typically require a minimum of 6 hours of direct sunlight each day. Indoors, you can supplement this with 14-16 hours of light from LED bulbs. Most countertop and vertical hydroponic systems have built-in lighting systems.
DLI: DLI, or Day Light Integral, is the total amount of light that plants receive in a 24-hour period. A 2019 study shows that a DLI range of 11.5-17.3 mol/(m2· d) is optimal in the quality and efficiency of strawberry propagation.
Temperature: Keep the air temperature within the 50-80ºF range for your indoor strawberries. Their roots are vulnerable to warm water temperatures. A little bit of cold can bring out the flavor of strawberries.
Humidity: Maintain 60-75% ambient humidity. Lack of air moisture can negatively affect calcium uptake and fruit quality. To avoid fungal diseases, install a fan nearby for air circulation.
Flow rate: Keep the flow rate at 1.6 l/m. If water flow is too high, it might stop root growth and hinder iron uptake.
Step 4 – Regulate the nutrient solution and water level.
Strawberries are highly sensitive to the balance of pH and nutrients in the water reservoir of a hydroponic system. Use a pH meter to regularly check for acidity levels. Both low and high pH values will cause problems with nutrient uptake.
pH levels: pH, or Power of Hydrogen, is the measure of how acidic or basic the water in a hydroponic system is. A pH range between 5.5 to 6.2 is ideal for strawberries. Some people use vinegar to keep pH down.
EC: EC, which stands for Electrical Conductivity, is the total measure of mineral salts and nutrients in a hydroponic solution. For strawberries, 1.0 to 2.0 dS m-1 are the recommended EC values.
TDS: Total Dissolved Salts (TDS) indicates the strength of a nutrient solution in a hydroponic reservoir. It is measured in ppm (parts per million) which is the number of milligrams of nutrients found in every liter of water.
For strawberries, 500-800 ppm is best. Going beyond this range can cause brown leaf tips and reduced flowering. If your hydroponic system isn’t already equipped with one, you can purchase a cheap digital meter to measure TDS.
Nutrient solution: The correct ratio of NPK plus some micronutrients is essential for strawberry growers. You can ask your hydroponic supplier if they have a nutrient solution that is ideal for fruit production. We recommend the MasterBlend 9-12-34 Strawberry Formula.
Once your plants start to flower, you can enhance the potassium and phosphorus levels to increase fruit yield. You can also add Cal-Mag and rainwater to get sweeter strawberries.
Step 5 – Prune your plants.
In the early stages, snip off any flower buds and long, leafless runners (also called stolons) to give your strawberry plants the chance to develop their foliage first. More leaves means they will have more energy to bear more fruit.
If you intend to propagate your stock plants, submerge the tip of a runner in a cup of water until it develops roots. Eventually, you can cut this off and start a new strawberry plant.
Step 6 – Pollinate the flowers.
Strawberries have both male and female flower parts. Although strawberries are self-fertile, you can manually pollinate them to obtain bigger and better-shaped berries.
Outdoors, the presence of wind and the activity of bees contribute to the pollination process. Indoors, hand pollination is essential in fruit production. Strawberries may look deformed if the pollen grains from the Stamen fail to reach each individual Pistil.
Using a cotton bud, a make-up brush, or a pipe cleaner, gently dust off the pollen from the outer edges of each flower into its inner circle. You can also shake the plant to help with pollination.
Pollinating our strawberries 🍓 #farmtoschool #realschoolfood #farmtoschool #farmtotray #verticalfarming #towergarden #hydroponics #indoorfarming #organic #elementaryschool #strawberries pic.twitter.com/elg6Kh018o— Hopewell Elementary Vertical Farming Initiative (@HESVerticalFarm) March 13, 2019
Step 7 – Harvest your strawberries.
Strawberries will typically bloom 2-3 months from the time they are planted as seeds. If you started with bare-root stocks, you will simply need to wait for the first flowers. After that, it will take about 4 weeks for the first batch of strawberries to ripen.
Harvest the strawberries when they ripen. The more fruits you pick, the more will grow in their place. Each plant will produce around 5-10 strawberries per week and will continue to do so for many months.
Once the roots grow too long for the hydroponic system, growth and yield will slow down. Older plants will need to be replaced with younger ones.
A 2020 experiment reveals that coating hydroponically-grown strawberries with chitosan and calcium gluconate can prolong the storage period until 10 days without decay.
Step 8 – Clean the system and repeat.
As time passes, evaporation and absorption of water by the plants’ roots will change the balance of pH, EC, and nutrients in the hydroponic reservoir. These factors, along with microbial build-up, will affect the health of your strawberry plants.
You will need to refill or fully replace the water at regular intervals, as well as clean the tank and rails once a month. However, timing is incredibly important.
When the water level runs low, nutrients become more concentrated. This can stimulate faster root growth and increased fruiting, but extended exposures can eventually damage strawberry plants.
Top-off: Instead of completely replacing the water outright, you can simply refill the amount of water that is displaced. Top-off the water every 2-3 days and keep track of the total volume that you add. This will help you decide when a full water change is due.
Topping off is important because it allows the plants to slowly adjust to gradual changes in the water content. On the other hand, a sudden full water change can shock the plants’ roots.
Full water change: Depending on the size of the hydroponic system and the number of plants grown at a time, a full water change may be necessary every 1-3 weeks. Automated hydroponic systems usually have pumps that can drain the reservoir. You can also manually throw out the water.
System clean-up: Hydroponic plants have thin roots that are susceptible to pathogens and microbes.
Biofilm is a natural byproduct of plant growth. It’s typically a brown color and it grows on the inside of the pods, columns, and tanks. When biofilm accumulates, it can clog the pipes in a hydroponic system. Its presence can also invite fungi, viruses, and other parasites.
Algae is a green-colored organism that is formed when light reaches the surface of the growing media or the interior of columns. It competes with your plants by eating the nutrients and reducing the oxygen. Dead algae becomes food for harmful bacteria that can rot roots.
To clean your hydroponic system, disassemble the parts and scrub every nook and corner you can reach. Dilute food-grade hydrogen peroxide in water to get rid of biofilm and algae build-up. While cleaning, remove any particles that may have settled at the bottom of the rails.
Best Strawberry Cultivars For Indoor Growing
Outdoor strawberries have a conventional harvest period of 3 weeks in the month of June. Indoor hydroponic cultivation extends the growing season all year, resulting in high yields.
When growing strawberries indoors, you can choose ever-bearing or day-neutral varieties. They are not sensitive to changes in the length of day and other weather conditions. This means you won’t need to vary the number of hours of Grow Light exposure to trigger fruiting.
You can expect ever-bearing and day-neutral varieties to produce strawberry fruits all year round, as long as you provide them with ample light and nutrients, and keep the temperature between 35-89ºF.
The only limiting factor is when the roots grow too big for the hydroponic system, at which point you’ll have to replace the stock plants with their daughter plants that you might have propagated before.
Popular day-neutral cultivars include San Andreas, Selva, Sweet Ann, Tribute, Tristar, and Alpine strawberries.
A 2016 experiment on 11 hydroponically-grown strawberry varieties reported that Florida Radiance, Monterey, Evie 2, Portola, and Seascape were among the highest-yielding cultivars.
Another test in 2014 showed that the Festival cultivar had the highest yield, while Oso Grande and Albion had the biggest fruit weight.
Pests And Diseases To Consider
Although hydroponics reduces the presence of soil-based diseases, some persistent pests will still find their way to your indoor garden. Here are some of them:
- Spider Mites: Spider mites are smaller cousins of spiders, but they feed on plant sap instead. They thrive in a dry environment and can be found crawling on the underside of leaves. You can use AzaMax or hydrogen peroxide to control them.
- Powdery Mildew: Powdery mildew is a fungal disease that covers the surfaces of leaves with a white, sticky substance. This hinders photosynthesis and leads to yellowing and eventual loss of foliage. You can spray your leaves with diluted neem oil or a copper-based fungicide to fight powdery mildew.
Research published in 2004 found that potassium silicate suppressed the growth of powdery mildew on hydroponic strawberries for up to 4 months! Impressively, the presence of potassium silicate did not significantly alter the ratio of other macronutrients.
- Rhizopus rot and Mucor rot: Fruit rot can affect overripe indoor strawberries. It thrives in warm temperatures that are essential for fruiting. To avoid rot, you can harvest strawberries as soon as they ripen.
A vertical grow tower is the best option for growing your own hydroponic strawberries at home. It is cost-efficient in the long run. It offers more yield, less space, and less effort compared to traditional gardening methods.
A 2019 study revealed that hydroponic strawberries contribute twice as many minerals that are safe within the daily intake of humans than any other fruit. Additionally, research from 2016 showed that hydroponic strawberries had significantly higher fruit yield and plant survival rate compared to soil-grown strawberries.
Instead of battling soil-based pests in the garden and waiting for the warmer seasons to plant food, you can simply set up your own hydroponic system indoors and enjoy a harvest of fresh strawberries all year-long!