Cleaning and maintenance are no one’s favorite topics, yet they are critical aspects of any farming operation, from one that sits atop a kitchen counter to one that comprises hundreds of acres of greenhouses. Simply put, you cannot take risks when it comes to pests or diseases, or you may endanger your entire system.
That’s where the dirty work comes in.
Cleaning
Regular old cleaning, probably the least fun kind of maintenance, is a must for any aeroponics system. Yet it’s absolutely critical that you sterilize and sanitize like it’s your job. Because if it is your job, then it’s the only way you’ll stay in business. (And if you’re a hobbyist looking for more off-the-grid food, then you’ll have wasted your money without excellent cleaning practices.)
Aeroponics isn’t hydroponics, but it’s still a pretty wet endeavor, and moisture attracts mildew, mold, algae, fungus, and more. For that reason, you need to keep things tight, or you’re inviting problems. Regular cleaning should include:
- Scrubbing all elements to which plants are exposed, including catch basins, growing containers, and surrounding areas
- Watching for build-up of salts and nutrients, which can clog misters, degrade equipment, and burn plants
- Removing dead or wilted leaves from plants
While your system is in operation – i.e. there are currently plants growing in it – you should use hydrogen peroxide. This is an excellent sterilizer to help you fight microbes, but will not harm plants should it contact them in small amounts.
In between grow cycles, you must flush the entire system with a harsher cleaning agent, bleach being the standard. First, clean out the reservoir, then run a diluted bleach solution through all pipes, tubing, sprinklers or misters, grow chambers, and so forth. Use a scrub brush to get into the corners so that you don’t accidentally leave a pathogen to take root once you’re operating again.
After you’ve cleaned everything, do a thorough flush with plain water to ensure you get rid of any harsh chemicals that might hang around, which can harm your plants. Then let everything dry naturally before installing a new round of specimens.
In general, you should plan to do a basic clean of your growing chambers about every 4 weeks, with a thorough clean of the entire system between every crop cycle.
Maintenance
In addition to cleaning, you’ll need to maintain your system. High crop yields and minimal resource use – the entire point of aeroponics – depend heavily on the system running smoothly and efficiently, within specs. If you allow it to fall off balance, then you’re sacrificing plant health, nutrition, and potential harvests.
In addition to cleaning your growing chambers out every month or so, you should plan on replacing the water and nutrients at that time. Keeping them fresh minimizes the chances that your plants will suffer an infection of any kind, and it also gives you a chance to remix your nutrients and ensure they’re exact. When you change the solution, make sure to record the date somewhere so you know when to change it again.
In between cleanings and water changes, you should always monitor the levels of:
Fertilizer
Specific nutrients, the cocktail of which is unique to individual plants, consist of a mix of calcium, nitrogen, magnesium, sulfur, phosphorous, potassium, and others. Your exact recipe will depend on what you’re growing, so make sure to update it if you install different plants in your aeroponics system the next go-round.
The good news (and the bad news) is that nutrient deficiencies occurring in aeroponics plants look very much like those in regular soil-growing plants. They are less likely, since you can control the mix of nutrients so effectively, but it does happen. If you believe you’re seeing a deficiency, you can check the signs using a reputable source, then test your solution and correct for the lack.
pH
The pH, a measure of how acidic or alkaline a system is, matters quite a lot to healthy plant growth. The pH scale ranges between 0 (extremely acidic, such as battery acid) and 14 (extremely alkaline, such as drain cleaner). At 0, the concentration of H+ ions is incredibly dense, while at 14, they are incredibly sparse. Both conditions make a solution highly reactive, which means it can easily corrode and burn anything with which it interacts. For that reason, most living things like a pH nearer the middle.
While the human body prefers a pH of neutral (7), plants in general tend to appreciate slightly acidic environments. You can assume a range between 5 and 7 is okay. However, it’s best to look up the exact preferences of each plant you’re growing and match the pH to that. The more carefully you tailor your environment to your crop’s needs, the better yield you’ll get and the more nutritious your produce will be.
Happily, it’s easy to test for pH using strips available in any home improvement or garden store. It’s also easy to correct it using additives, so if you find your pH is off, simply adjust it upward (more alkaline) or downward (more acidic).
Electrical Conductivity
Electrical conductivity, or EC, has implications for the health of your plants. As we’ve discussed in previous posts, “The electrical conductivity, or EC, of your reservoir can give you special insights into how your plants are doing. Plants are designed to only absorb what they need, at the time that they need it.”
Ideally, your plants have the exact nutrients they need at all times, but that’s not realistic. Instead, you must create a routine for continuous measurement and adjustment: “If during a cycle, you find the EC readings are low, then the plant isn’t taking in enough nutrients or the solution you’re using isn’t strong enough. When the EC readings go higher, the nutrient solution is too strong, and may need to be diluted.”
It may take some time to become familiar with these processes, but with dedication, it will become second nature.
