Hydroponic Grower’s Guide to Trimming and Pruning

Like any other cultivated plant, a hydroponically grown plant occasionally needs a little taken off the top—or bottom—to look good and grow even better. But just in case you’re feeling skittish about grabbing the scissors or shears and clipping away at your green progeny, take heart. With a little basic knowledge, you can learn how to cut them down to a more efficient size to let them grow heartier than ever. Here’s a hydroponic grower’s guide to trimming and pruning to help you get your start at cutting smart!

Why Trim and Prune?

You’d think that if you let your plants grow unfettered, you’d guarantee bigger blooms and yields. Not so. Let’s begin by defining the terms trimming and pruning. Believe it or not, they describe different processes, though you may hear people using them synonymously in everyday gardening talk.

Trimming refers to, in so many words, giving an overgrown plant a haircut. When you trim, you’re cutting away all the unnecessary extra stuff weighing down the plant’s branches or stems. It can also open it up to more sunlight and air—encouraging the development of lateral branching as well as buds and blooms—and helps fight insect infestation. Trimming can also cut down on the need for pruning. And speaking of pruning...

Pruning is the specific removal of branches and stems from a plant. You cut away dead, injured, and simply loose parts of the plant to improve its health by stemming infection and infestation and encouraging new growth. This way, the plant can distribute water and nutrients more evenly to healthier parts of the plant. Pruning is also extremely useful when transplanting, harvesting, grafting, and increasing yields. So trimming and pruning are kind of the same—but also different.

Trimming, Pruning, and Hydroponics

Trimming and pruning seem self-evident with outdoor plants. If you have bushes on your front lawn, you need to keep them neat by trimming and reshaping the plants. Likewise, you need to prune dead branches from an old tree to encourage new growth, discourage destructive insect spread, and avoid a safety hazard. Come to think of it, it’s not so different from trimming and pruning hydroponic plants after all—though perhaps with fewer falling tree branches and much more attention to the roots.

The Right Tools

Think smaller when it comes to trimming and pruning hydroponic crops. No loppers, two-handed hedge shears, or pruning saws necessary here—and put away that chainsaw. You can make do with a small set of stainless-steel trimming or pruning scissors. Consider picking up some steel mesh gloves, as well, to avoid any accidents with the blades. Spring for a slightly more expensive pair. They’ll last longer. Pick up a sharpener to keep them in peak cutting condition as well. Also, when you start trimming, remember to keep the blades clean and sterile, especially between plants. You don’t want to accidentally spread disease from one sickly plant to all the others.

When and Why To Cut

Most experts advise trimming and pruning early in the growing season and as issues reveal themselves. For some plants, that be no more than two weeks into their development, but note whether the plant seems ready for it. Obviously, remove dead and diseased branches, cutting them off at a 45-degree angle just below the brown or dead area. If a branch on a larger, leafier branch appears to be dead, cut it off, but leave the larger branch alone. If you see an incoming bud, make sure to clip a short space above the bud and at an angle. Trimming off dead flowers at their base will allow new ones to bloom in their place. Look for injured parts of a plant, and prune those branches since such places can be entry points for insects and disease.

You can also encourage growth by removing leaves and sucker branches that can look unsightly while drawing off water and nutrients that could better serve other parts of the plant. Don’t remove too much from a plant. Some sites recommend taking no more than 10 to 20 percent of a plant’s foliage at a time. They need time to regrow stronger and healthier replacements. While you’re trimming, check your grow pots and other equipment for dead leaves and flowers and other detritus floating in the solution or simply laying on the ground. Again, those can attract disease and bugs, encourage mold and mildew growth, and interfere with the efficiency of your hydroponics equipment. It might sound funny, but give your plants and setup a gentle wiping and dusting as well. Keeping them clean leaves them more open to the light.

Down To the Roots

Here’s that little difference between pruning and trimming indoor and hydroponic plants. Give your plants’ root systems a good look to determine if they could use some clipping as well. Healthy roots will appear white and feel smooth. Discolored (mostly brown) roots are likely infected with bacteria. Keep in mind that discoloration can result from whatever you use in your nutrient solution, but healthy roots won’t appear withered, feel slimy, or break off easily. Clip these off to encourage healthier growth, but steer clear of the root crown where all the individual roots come together. Cutting too close could kill your plant.

Tips and Techniques

Those are the basics of our hydroponic grower’s guide to trimming and pruning, but here are few more steps, tips, and techniques to ensure healthier, happier plants. First, keep in mind that most hydroponically grown plants can last for a brief time away from their pots and the nutrient solution, so take the time to clean and sterilize your pots before replacing the plants. Some sites recommend introducing B vitamins to your nutrient solution several hours before you prune to motivate plants to heal faster. After pruning, consider adding some fertilizer to the solution to keep things growing. Prune more infrequently during the crop cycle so as not to place too much stress on them. On the other hand, while fruiting, consider pruning and limiting fruits to foster larger and better-quality fruit. Finally, after the harvest, certain crops will require additional trimming with a dedicated hydroponic trimming machine.