Let us take some time to look at how the operation works. This means that we will be exploring the different kinds of growing mediums available to us to see what works best for which kinds of setups. We will also explore how we seed our hydroponic gardens, how we light them, and what we do when the time comes for trimming.
Growing Mediums
When it comes to what medium we use in our grow trays, there is a ton of variety available to us. This can be a little intimidating at first when you aren’t sure which medium is right for you and the gardening that you are looking to do. We must choose a medium that works with the plants we are planning to plant. This means that we have to take into account things like water retention and pH balance.
Before we look at the mediums themselves, a quick word on the requirements of the different systems. The way that each system is set up and works say a lot about what kind of growing medium works best. For example, a drip system functions best when it is using a growing medium that doesn’t become too soggy. In contrast, a wick system likes a growing medium that absorbs and holds onto water and moisture with ease. While nutrient film technique systems want to avoid a growing medium that easily saturates, an ebb and flow system will want to have good drainage and a growing medium that doesn’t float. Considering the mechanics of your system of choice is the first step in deciding on a growing medium.
Coco Coir
An organic and inert grow medium, coco coir is made from the frayed and ground husks of coconuts. When it comes to pH, coco coir is very close to neutral. Coco coir retains water but also allows a decent amount of oxygen to get through which helps the roots. This medium is primarily used in container growing or in hydroponic systems of the passive variety such as wicking. Because it can clog up pumps and drippers, it is not a great choice for more active systems such as the ebb and flow system.
Lighting
When it comes to lighting, there can be no substitute that makes up for the power of the sun. There is a reason that spring and summer are such beautiful, green times of the year. The sun is the most powerful lighting source available for plants.
But we’re not going to be using it here, despite all that. Instead, we are going to be using artificial lighting so that we have complete control over it. Not only that, but many of us are interested in hydroponics because we don’t have access to an outdoor space in which to garden. If you live in an apartment, chances are you’re reading this because it offers you an option for growing your food without having to leave home. If you can set up your hydroponic garden so that it takes advantage of natural sunlight, that’s great! But if you can’t, you need to look into artificial lighting and that’s what we’ll be exploring.
There are tons upon tons of options available for lighting. So many that it can be overwhelming if you are new to the topic. What size light do you want? What color spectrum is it supposed to be playing within? Heck, how much light is the right amount? It can truly be daunting. But don’t worry, it’s a lot easier than all those choices make it seem.
Tackling the amount of light, we can use the sun as a basis for this. If we were growing plants outside, we can expect them to need about five hours of direct sunlight and another ten of indirect sunlight. This means five hours soaking in the sun and ten hours being outside but getting a little shade. Using this system, we can adjust our artificial lighting accordingly. Using artificial lights, we should be giving our hydroponic garden about fourteen hours of bright light and ten hours of darkness. Doing this system every day imitates the sun’s natural lighting cycle. Don’t skimp on the darkness, either. You might think that more light means faster growth but plants are just like us in that they need to rest and metabolize the nutrients that they are getting.
Some plants need more light, some plants need less. You can think of the fourteen-ten system as a general. This system works well for most plants and can be a successful route to take with your garden. But you should be aware of the light requirements of your plants.
Some plants like short days, which means they want longer periods of darkness in which to function. With these plants, being exposed to more than twelve hours of light per day can cause them to not flower properly. Strawberries and cauliflower are examples of short-day plants. The short-day cycle works to imitate the shorter days of the spring in which these plants like to grow.
Long-day plants are those that want to get up to eighteen hours of sunlight per day. These are mimicking the longer day cycle that comes with the summer season. Examples of long-day plants include lettuce, potatoes, spinach, and turnips. Because they like more light, you wouldn’t want to mix long-day plants with short-day plants in the same growing tray. If you do, expect to pick a lighting cycle that meets the middle of long and short needs.
Some plants are more neutral. These plants tend to be flexible and can work with more or less light as needed. Eggplant and corn are examples of these sorts of plants. Day-neutral plants can be mixed with either short-day or long-day plants and grow equally well.
Because you want to mimic the sun, the best option for lighting your hydroponic garden is to get a timer. If you set up an ebb and flow system earlier, you probably have already gotten yourself a timer to make sure that you are letting your nutrient solution drain before washing over them again. We use the same kind of timer, only instead of being set up to a pump, we have set it up to our lights. How long you set the timer for will depend on what you are growing and their light needs as discussed above.
When it comes to the lights themselves, we need to get into a discussion on bulbs. The most popular bulb to use in hydroponics tends to be between 400- 600 watts and of a kind called a High-Intensity Discharge. These bulbs tend to be encased in glass (with gas and metal salts thrown into the mix) and they create light by sending electricity between two electrodes. The gas helps the bulb to create the arc and the metal salts evaporate to make white light. They come in two types: high-pressure sodium bulbs and metal halide bulbs.
The metal halide bulb works as an all-around light that most vegetables will love. If you have to choose between metal halide or high pressure sodium bulbs, the metal halide is the better choice. They tend to be expensive, upwards of $150 for a 400-watt bulb but they only need to be replaced every other year, though they may decrease in efficiency earlier.
High-pressure sodium bulbs are best used for the flowering stage of our plants. These are even more expensive than metal halide bulbs but they tend to last up to twice as long. However, they do also lose efficiency like the metal halide bulbs.
If we want to increase the efficiency of our bulbs, we can use a reflector hood. This is a reflective case that goes around the bulb and increases its effectiveness by bouncing the light around. This helps the light to hit our plants from different angles so that we can get a more effective spread onto our garden. It also serves to get a little more heat out of the bulbs, as the light beams are now crossing each other and make up a denser section and thus carry more heat and power.
So when it comes to lighting, if you can only get one bulb, go out and get yourself a metal halide bulb and a reflector hood. Get yourself a timer and make sure that you set it to the needs of your plants. When buying plants, you almost always will receive a tag with some information about the light requirements of the plant or the seeds. Following this and setting up an appropriate timer will make sure that your plants get all the light they need.
Gravel
Gravel doesn’t absorb or retain moisture. Instead, gravel works to give an anchor for the roots of the plant. For this reason, gravel works best in a system that doesn’t require a ton of retention such as a drip system or a nutrient film technique system. Any system that keeps the roots of the plant in constant contact with the water can make good use of the gravel.
In some setups, such as the bucket-based drip system we saw above, gravel is used as a bottom layer in the pot. This allows for better drainage as the water has passed through whatever medium made up the top layer to find gravel which doesn’t retain it whatsoever. It also serves to add some weight to the bottom of your tray which can help to prevent spills from wind or other elements.
If you are using gravel, make sure to give it a proper wash before use in the system. If you want to reuse the gravel, make sure to wash it yet again. We do this to prevent salts or bacteria from getting into the hydroponic system and causing issues such as burnt roots, high levels of toxicity, and the like. Jagged gravel can also damage the roots so it is best to use smooth gravel as a way of avoiding this.
Trimming
The final step in the operation cycle of our hydroponic gardens is trimming. When plants are out in the wild, nature plays the role of gardener and trimmer. These plants can go many years, sometimes even their whole life, without being trimmed or pruned. Once you bring your plants indoors, either inside with a hydroponic setup or in a greenhouse, people immediately start reaching for those pruning shears. When we consider the image of gardening we have in our heads, we can see that movies and TV have told us again and again that we want to prune our plants. Characters are always doing it!
But the truth is that if we don’t prune our plants properly, we risk hurting them. To be clear, this means that the pruning we are doing is the thing that can hurt them. Not a lack of pruning. Improper pruning causes unneeded stress on our plants and can do some serious damage to them, even going so far as to leave them vulnerable to disease or infection. This is because each time we prune our plants, what we are doing is opening up a wound. We cut off a branch, and we have just torn open our plants. Where there was a hand, figuratively, there is now just a stump. If you think about the human body, you can see why this could easily go wrong. We need to give our plants’ bodies the same respect we would give another human’s. This means that when you go to prune, make sure that you sterilize your cutting instrument between every cut. This can be done as simply as mixing four parts water with one-part bleach and dunking your shears into the solution before each cut.
So if pruning our plants can be so harmful, what are the reasons that we choose to do it? There are quite a few reasons. One is that we want to control the overall size of our plants. If we are growing inside, we may prune our plants to prevent them from reaching out and getting in the way of walking areas or the television, and things like that. This is the same reason that we cut tree branches when they get too close to power lines. We might also cut our plants to improve their health and the quality of their flowering. If a particular piece of the plant is dead and rotting, we need to remove that piece to promote the plant’s health. We may also want to remove bits that didn’t flower properly, that way the healthy flowering parts have more room to breathe and space to expand. This will also stop the plant from spending energy trying to repair damaged parts and instead it can use that energy for growing.
One reason NOT to trim your plants is to increase the overall yield. Trimming doesn’t help our plants in this way. Rather than trim to increase, we should be trimming to promote better health.
that healing is promoted and the time it takes to heal is reduced. Because pruning the plant is so stressful and healing takes energy, you should only prune when necessary and you shouldn’t just make cuts willy-nilly. It might be best to prune a little, wait for the plant to heal, and then prune some more rather than do it all in one big burst.
If the reason you are pruning your plant is that it is growing too high for the area you are housing it in, consider doing what is called “topping.” When we prune in this manner, what we are doing is cutting off the top of the main stem of the plant. Once we cut, we are going to then pinch it together as we do with any of our cuts. However, pinching the top of the main stem after a cut gets the plant to release floral hormones which will cause the plant to begin focusing on growing sideways rather than upwards. This same technique can then be applied to these lateral branches to achieve a reverse effect where it begins to grow upwards again. In this way, topping allows us to get some control over the growing patterns of our plants. Topping also leads to a weird effect where gardeners have noticed that plants that have been topped tend to produce more small fruit. Meanwhile, plants that haven’t been topped tend to produce less fruit but of a large size.
If you are pruning to remove damaged and dying leaves, you should only be removing leaves that are more than half damaged. These leaves are no longer providing the plant with energy and instead are draining it of some in its attempts to heal them. There is a misguided idea that if a plant’s leaves turn yellow, you should immediately remove them. However, turning leaves yellow is the plant’s way of trying to tell you that something is wrong. It typically means that the plant is undergoing a lot of stress. This could mean that it isn’t getting the nutrients and light it needs or maybe it is even a sign that the plant is dealing with an insect problem. When your plant’s leaves start turning yellow, you should look at what the plant is trying to tell you before you start to cut it. If you fix the problem, quite often you will see the leaves take on their healthier green color again.
So, when it comes time to start pruning your plants, make sure that you sterilize your instruments, think about how much stress you are putting on the plant, and only make necessary cuts. We want to grow healthy and fruitful plants and this means respecting the bodies of your plants like you would respect your own.
Perlite
Perlite is an amendment to our growing mediums, which means that it is used to improve an existing medium rather than just being used on its own. You make perlite by the heating glass or quartz sand, though of course we don’t have to make it ourselves but can buy it from any gardening store. Perlite helps to improve drainage and aeration when mixed in with another growing medium such as coco coir.
Because we are using a nutrient mix and not just pure water, we have to be concerned about nutrient build-up. The nutrients in our solutions can get absorbed into the growing medium and lead to a build-up of toxicity which risks killing off our plants No gardener wants that. The extra drainage that perlite offers will help to prevent this build-up and will help in making sure that our plant’s root system gets the oxygen it needs to grow. Perlite comes in different grades from fine and medium to coarse. The kind you need will be determined by the rest of your potting mix. Perlite should never take up more than a third of your mix, however, as using too much will cause it to float and floating perlite doesn’t offer the benefits, we wanted it for in the first place.
Vermiculite
Vermiculite is a lot like perlite. It comes in three different grades, again ranging from fine and medium through to coarse. Made by expanding mica through heat, vermiculite is another soil and potting mix amendment. This means that vermiculite is mixed with another growing medium to get the best results.
Vermiculite sort of works like the reverse perlite. Where perlite helped with the drainage of our growing medium, vermiculite helps our growing medium to retain water. For this reason, vermiculite can often be seen mixed with perlite for use in hydroponic systems of the passive variety such as wicking systems.
Seeding
When it comes to getting plants into our hydroponic system, we have two options available to us. We can go to the store and we can purchase a seedling which we then transplant into our system. Or we can purchase seeds and we can raise the plants ourselves. In this section, we will be looking at this second option to see how it is we can turn seeds into wonderful plants for our hydroponic gardens. But this means that we will also be exploring the first option because when our seeds are ready to be moved into our hydroponic setups, we will be transplanting them as seedlings.
There is a lot of satisfaction to be found in growing a plant out of a seed. They start as tiny grains and yet can grow to be such big and luscious plants. It is a wonderful feeling to know that you are the one responsible for making that come to pass. But there are benefits to growing from seed beyond just the feeling that it gives us.
When you purchase seeds, you are getting many chances at growing the plants you want. Not every seed will take but enough of them will that you can easily get a ton more plants through seeds for the same price that you would go out and get a single seedling. This makes it a cost-effective approach, as well as one that just feels awesome. Purchasing seeds also gives you more control over what you grow, as you are not limited in options to only the seedlings that the store had available when you went looking. This means that you can be the one to choose what you grow and it could be rare and esoteric plants or just some lettuce and herbs. The choice is up to you.
If you grow the seeds directly in the hydroponic system which you are planning to use, then you don’t have to worry about transplanting your greens into a new system. This can be a way to avoid causing plant trauma or ending up with root damage. Transplanting into the system can also be a way to introduce disease or pests into your garden and we want to avoid this whenever possible.
When we decide that we are going to start with seeds, it does cost us a little bit of money upfront because we need to create a few things for them to start to grow. However, this cost is mostly when just beginning. If you have already started with seeds before, you can expect to save some money when you come to the next. The good news is that you don’t need to go out of your way to buy super-specialized equipment or materials to begin growing from seeds. All of the materials that you pick up can have used at other steps in the process.
Assuming that you have already gone and picked out some seeds, what do you need to get them started in your hydroponic garden? The first thing we need is a grow tray. This can be one that we have set up before, or we can make one with a dome shape to it to create a miniature greenhouse. Don’t worry if you don’t have one that fits that description, this is just one way to help our seeds out. We can use whatever grow tray we have available.
We want to make sure that we position our grow tray so that it gets good light – if the plants are the type that likes lots of light. We also want to make sure that the tray gets a good amount of heat. Getting a heating pad that goes under or making sure it is kept in a warm area will help to make sure that sprouting begins to happen.
At this stage, we have two options available to us. Our grow tray can be used specifically just for these seeds, which would mean that we have to transplant them when they have grown into seedlings, or we can use a grow tray that is ultimately part of the hydroponic setup itself. Going the second route can be useful because it avoids the traumas that can happen when trying to transplant our seedlings.
After we have a tray set up, we are going to want to go out and get or make some starting plugs. These are little compact masses of solid growing medium that are used specifically for the growing of our seeds They tend to be made up of composted pine and peat or other organic matter. We can purchase them or make them, as they are little cubes of the material with a small hole for us to put our seeds into.
Open up your plug and drop a couple of seeds inside of it. We do a couple just in case any of the seeds don’t want to take. If multiple take, we can always remove the weaker plant so that the stronger one can grow even better. After you have dropped your seeds into the hole, tear off a tiny piece of the plug and use it to block the hole. You do this to prevent your seeds from drying out or getting knocked out of the plug.
In the grow tray, you will need about an inch of nutrient solution, though you only want that inch to be at half the strength that it would normally be. Place the seeded plugs into the tray. You can expect to start seeing some sprouts emerge within four or five days of planting. Make sure that you keep an eye on the water levels throughout this period and add more nutrient solutions as the levels decrease.
That’s how you grow from seed. Now, if you have set this up in your main grow tray, you don’t have to worry about transplanting them later and you can just let them grow and continue watching them as you would any other plant in your garden. If you started them in a tray specifically for seeds, however, then you are going to need to transplant them into your system.
As your seedlings start to grow stronger, you can stop worrying about halving the strength of the nutrient solution and begin them on the regular strength solution mix. When you start to see the roots of the seedlings coming out of the bottom of the starter plug, this is the sign that you can now begin transplanting them. This could be anywhere from two to four weeks; it all depends on which plants you are growing.
Now that the seedlings are ready, you are going to take them and gently move them over to your hydroponic setup. To do this you are going to take the seedling and the cube together. If you want to open up a spot in your garden, gently place the cube and seedling into said spot and then cover it gently with your growing medium of choice. After this is done, you will want to water the plant from the top for a few days so that it grows out of its root system and naturally seeks out water and nutrients.
And that’s it! Now you have grown your very own plant from seed through to seedling and through transplanting and developing a root system naturally. Working with seeds this way allows us to take more control over what we grow and to make sure that we aren’t introducing any problems into our garden that may be found in the seedlings available for purchase at the store.
Rockwool
One of the most popular of the growing mediums, Rockwool is made through the heating and spinning of certain silica-based rock into a cotton candy-like material. This creates a firm material that tends to have the ideal ratio of water to oxygen that our plants’ roots love. It also is mostly pH neutral, which is always a plus.
It can be found in a bunch of different shapes and sizes with the most common being a cube shape. These cubes are awesome for starting seeds (which we’ll look at more in just a moment). These smaller cubes are often used to begin the growth of a plant before being transferred into another growing medium.
Because of the versatility of Rockwool, it can be used for starting plants before transferring into another medium for deep water cultures or nutrient film technique systems. It can also be used for drip systems and ebb and flow systems without the need to transfer.
Mixing Your Growing Medium
When it comes to which growing medium is the best, it depends on the job that you are looking to have it tackle. Once you have an idea of what you need, you can begin the task of mixing it all. Many different projects on the market offer pre-mixed growing mediums and these can be a great way to save a little time and get what you need right out of the box.
However, some of us are a little more specific and we like to get our hands dirty in this part of the process. Mixing your growing medium can be a great way to make sure it is 100% the way you want it to be. But this can be a little tricky if you are new to hydroponic gardening and don’t know what combination of mediums is best. Part of getting into anything new, and hydroponic gardening is no different, is that you have to accept some uncomfortable moments and you have to accept that you will learn from your mistakes.
For an example of one mixture, let us look at what Upstartfarmers.com have laid out in their discussion on soilless potting. They offer a formula for a mixture that is one-part coconut coir or peat, one-part perlite or vermiculture, and two parts compost. While the systems we have looked at aren’t focused on compost but rather on getting nutrients through our reservoir’s solution, this shows us a straightforward mixture. Notice that the perlite or vermiculite does not exceed 33% (or 1/3rd) of the total mixture.
