There are many people who are either just starting with hydroponic gardening or considering giving it a go. This can be for any number of reasons, but the main aim is to grow healthy fruits and veggies at home rather than purchasing them from the supermarket.
One question I get asked too often is “Can all plants be grown hydroponically?”, and today I decided to answer it.
The answer is straightforward, but the results tell a very different story.
It is possible to grow all types of plants hydroponically, but once you reach some types of plants, it isn’t feasible. Some things will grow, but they are actually hindered in their growth when raised in a water-based environment.
Here we will take a look at what can be grown, what shouldn’t be attempted due to various reasons, and we will also look at a couple of high-value crops you can grow in a DIY hydroponics system that might surprise you.
Factors That Can Determine What Should Be Grown Using Hydroponics
Before delving into what we can grow, and what is best left to other growing methods, we will look at what factors are involved in either decision.
All plants grow by different means, and if these are mixed in a hydroponics system, it won’t be possible to tailor the nutrient solution to match each variety. Even if you separate nutrients, the overall growing conditions might suit some plants, such as warmer climates, or you have ones that prefer a cooler environment.
There are shallow rooting plants and vegetables which are ideal, and then you have deep rooting tubers that require lots of depth and plenty of support. Things such as potatoes, carrots, and turnips among others can be grown when the conditions are tailored for them, but you can find they don’t taste any better than the varieties you can purchase.
Vegetables of this type also take up more space in your system, although they can be grown if you so wish.
In the same vein are vegetables like squash, zucchini, and corn. All these can be grown, but again, these are not suitable because they are surface-growing vegetables and spread outward. This makes any hydroponics system unfeasible for vegetables of this type.
Trees are pretty big, and on trees come fruits. But, once again, these can be grown using hydroponics. However, there are plenty of trees that are too big, and it makes no sense for any grower. But, there are some fruit trees that make very real sense to grow in a hydroponics environment.
Read more about growing trees hydroponically.
Mother Nature has one thing up her sleeve that we can’t mimic as passively, and this is pollination. There are many plants that have both male and female flowers. These become labor-intensive because there won’t be any bees inside your hydroponics environment, and learning how to manually pollinate plants can become a painstaking task.
One other factor which needs considering is if you are growing indoors, or you have an outside area. Some vegetables can’t grow as easily under grow lights as they can outdoors, but because you have limited space, taller crops make very little sense.
To summarize all this, you can grow whatever you wish, but the most significant limiting factor is the practicality of doing so.
Now, we will look at some of the best things you can grow in hydroponics in certain conditions.
Indoor Hydroponic Growing
Indoor hydroponics systems are used for a multitude of reasons. It can be that the local weather is harsh and growing outside doesn’t give plants much of a chance, or the growers live in the city and have no access to an outside area.
A system can be set up anywhere, as long as you provide everything plants need to grow. An indoor hydroponics system need not take up too much space, and can even add to the aesthetics of your home. Here we will run through all you need for indoor growing, and which plants are ideal for this type of system.
The space requirements can be as small or as large as you want. From a windowsill to a spare room or a basement, they all make ideal growing areas once you plan correctly. This is where plant size affects what can be grown, but for shorter plants, you can use shelving, or make use of an old table with lighting suspended from above.
One system that works effectively is growing towers because they use vertical space along an interior wall rather than flat growing areas.
One thing plants need to do is photosynthesize. This they must do to survive, or they will wither up and die, no matter how well you have your nutrients mixed for them. Even if you have some natural light, this may not be sufficient, so you need to supplement this with grow lights.
With this, you now have one more element which is under your control, and with the correct types of lighting, you can deliver plants with the ideal amount without relying on the sun. Most vegetables grow best when they have access to 14-16 hours of light, and this can be sunlight or simulated (artificial) light.
There are many lighting options, and it can become confusing which ones to opt for. To make things a little easier, we have listed all the lamp types:
- Incandescent lamps: inexpensive and can be purchased from hardware stores or nurseries. Sufficient for houseplants but not indoor garden systems.
- Fluorescent lights: ideal for growing herbs and plants which are not light hungry. While inexpensive, they are not ideal for budding or flowering plants because they don’t deliver enough light.
- Compact fluorescent lamps: these are bright while being efficient, and in some cases are better than the more expensive HID (High-Intensity Discharge) lighting systems. These are suitable for all plants, and because they run cooler, they can be placed closer to plants. Ideal for shelving systems.
- HID lamps: efficient but expensive. They are the brightest, and one 1,000 watts grow light can throw out the same light as 50 forty watt fluorescent bulbs.
- HPS (High-Pressure Sodium): These are one of the best bulbs you can use. However, they do have a few downsides. They are expensive to purchase, but they are economical to run. They produce a lot of heat, so they need to be used in air-cooled reflector kits. Lastly, they are not suitable for all growth stages. They don’t produce light in the blue spectrum which is needed for leafy growth.
Metal Halide (MH) bulbs are great to start plants off with, but when you reach the flowering stage, it is advisable to switch to an HPS bulb.
- 400 Watt: A five foot, or eight-foot square growing area needs lighting placed 1 to 4 feet from the plants.
- 600 Watt: A seven or ten feet square growing area needs lighting set 1.5 feet to 5 feet from the plants.
- 1000 Watt: An eight feet or twelve feet square growing area needs lighting set 2 to 6 feet from the plants.
Temperature and Humidity
Most plants and vegetables prefer temperatures in the 65 – 75F range. It might be the case you need heating or cooling depending on your location. This can be controlled by a cooling thermostat.
Humidity is also a crucial factor, and quick ways to see if you have a humidity problem are: brown leaf tips, your plants are looking puckered and withering, or they are losing their leaves.
To raise the humidity, you can quickly mist plants daily, place a tray of water filled with lava rocks close to your plants, or make use of a humidifier or misting unit in extreme circumstances.
Plants that are Ideal for Indoor Hydroponic Systems
- Vegetables: Chard, kale, salad greens, peppers, carrots, onions, cherry tomatoes, cucumbers, and beans.
- Herbs: Basil, parsley, oregano, chives, cilantro, and rosemary
- Fruits: Blueberries and strawberries, grapes
All other elements such as growing medium, nutrient mixes, and watering will follow the same patterns as other hydroponic spaces where you might possibly grow.
Everyday Hydroponic Vegetables
The list of vegetables that can grow in a hydroponics system is endless. We have seen which are ideal for indoor gardening, but when you have space in an outside area such as a hydroponic greenhouse, then the possibilities are endless.
It is easier to say you can grow everything, but vegetables that grow below the surface will need some extra care and tending to. Parsnips, potatoes, and radishes are some obvious culprits, although it is still possible with the extra effort.
We can go back to squash or vining plants, and in most cases, these are impractical for space reasons. However, beans are a great vining plant that takes really well to hydroponics without taking over. Seeds will germinate in around 2-weeks, and no special formulation of nutrients is required. They grow fast, and you will be picking plump beans like crazy.
Succulent plant varieties don’t take well to hydroponics because they thrive in drier conditions. Water-loving plants make excellent choices to grow in your hydroponic setup. Melons are one of the best examples of fruit that will thrive in this situation. If you have space and can support the plants as they grow, it is well worth checking cantaloupe and watermelons as two varieties.
Berries are a handy crop to grow, although out of all, it is the strawberry that is the easiest. One fruit that is very similar and can be grown using hydroponic methods is grapes, both varieties have been successfully grown so if you want some juicy table grapes or fancy a go at making your own wine, you only need a large area.
Almost all fruits can be grown in this manner, but it becomes astonishing when you learn you can grow bananas in a hydroponic system. Such is their liking to this system, there is the Super Dwarf Cavendish variety which produces small dessert bananas.
Citrus fruits are also capable of being grown, although these are in the dwarf tree variety rather than the full-grown versions. Either way, if you have space and can support the rooting system in your growing medium, there is no reason not to find an area to grow your own oranges, limes, or lemon trees.
Lastly, you can follow in the dwarf tree vein and find small apple trees that can be successfully grown hydroponically. Again, as long as you provide all the tree needs in the way of nutrients, support, and light, then there is no reason you can’t have your own miniature apple tree orchard.
High-Value Hydroponic Plants
Although you might be growing hydroponically for your own pleasure, if you have an established system, nothing is holding you back from venturing out and growing crops that can bring in some extra money.
With this in mind, you do need to be selective in what you grow, and not offer what can already be found. Choosing crops that offer a higher return than lettuce or leafy greens makes any venture worthwhile without added competition.
The following three crops can be profitable, but depending on where you live, there might already be a grower who is covering them. A little market research to what is, and what isn’t available can help make your decision, but for now, here are three great crops to ponder over.
This has to be one crop that doesn’t pop up on most people’s lists of what to grow in their hydroponic systems. In a way, they are a contradiction because they require less light rather than needing more. This can make them a tremendous indoor crop.
Mushrooms require a soilless growing medium and moisture. You can purchase ready-to-use kits, or you can learn how to create your own mycelia. The only light mushrooms need is for triggering their fruiting (they don’t photosynthesize).
It is easier to purchase a mushroom kit that comes with colonized media (compressed sawdust, hulls, or hardwood shavings). All you need to do is remove this from the packaging and submerge it into a bucket of water for between 6 – 12 hours.
These are then placed in a dark area that has a temperature of around 60 – 75F until it begins producing in several weeks. Once you have fully grown mushrooms and harvested them, you can re-submerge your brick again and repeat the process.
Most kits can be used around four times. The fun is in doing the entire process on your own. You can purchase commercial mushroom spawn. Here is a brief direction on how to hydroponically grow mushrooms.
- Place mushroom spawn in a sterile petri dish. This will go to form mycelia.
- When this has happened, take a clear container and mix the mycelia with sterile grain or rice. This acts as the food source while the mushroom colonizes. You can see colonization when it looks white and has surrounded the grain substrate.
- Now mix the mycelia with some vermiculite and a little water until it is like clay. Form this into cakes.
- Place in a hydro tank with clay pebbles and an air stone
- The water shouldn’t reach the surface, so the cakes sit on top of the pebbles. Water should be over 60F, and well oxygenated.
Basil is one of the best herbs to grow using hydroponics. It is sensitive to cold climates so for indoor growing or heated greenhouses where you have a hydroponic system, it is ideal. Basil is only available for a few months of the year, so a fresh supply out of season is welcome by many a chef.
Hydroponic basil also comes with more flavor than conventionally grown, and you might find you can sell it by the pound rather than a few ounces here and there.
Basil delivers the highest yields in an NFT set-up and likes things on the warm side. Temperatures around 70 – 75F and humidity at between 40 – 60 percent. They also love as much light as you can give them, be it sunlight or artificial lighting.
These are always a hit, even if you can only sell them to friends and family. In a hydroponics system, you have a good ten-month growing season, if not all year round. There are reports of yields being higher than conventionally grown strawberries to a staggering 4x what is usually harvested.
Red Gauntlet is a familiar favorite for indoor hydroponic growers which appears to deliver exceptional results. These are great for indoor systems when you are growing vertically, so a plant doesn’t need to give high yields because you have more plants in the same growing area.
Temperatures should be no higher than low 70F’s during the day, and no lower than the high 50’s at night. When you pick hydroponic strawberries, do this in the morning when they are at their sweetest.
As you can see, with space, time, and effort it is possible to grow most things using hydroponic methods. This doesn’t mean they should all be attempted. Because of the beauty of how the system works, when there is a need for plants to be grown using these methods, we already know it is possible, and all that needs changing are the means of supporting larger plants and trees.
Although growing some varieties is not practical for the home grower, it isn’t to say these things aren’t practical, in areas where it is hard to grow nourishing foods and fruits.
We can make fruit trees smaller to fit into our hydroponic systems, but the time will come when the systems become larger to accommodate full-sized trees.