How To Protect Your Hydroponic System From Pests

One of the great advantages of using hydroponics as your basis for growing plants is that, because no soil is used, the risks of pests and disease getting to your plants is very minimal. However, you can’t completely rule out that some pests may be able to get in. No system is 100% safe. So there are some practical tips on how to protect your hydroponic system from pests.

Better be warned what to look for and keep the little bugs out, rather than get an unpleasant surprise one day. Here are a few insects that will be most likely to cause problems.

Aphids

Aphids can attack your hydroponic system, especially in cases where nitrogen is abundant in the food source. Aphids can be seen around the stems of plants and can be of several colours.

Whiteflies

Whiteflies are easy to spot, appearing similar to tiny moths, around 1mm in length, and are difficult to catch.

Spider Mites

These are less than 1mm long and, despite their small size, they can cause real havoc in any hydroponic system. Under a microscope, they appear to resemble very tiny spiders, and their size means that they can escape detection until it’s too late.

Fungus Gnats

The larvae of the fungus gnat are the problem rather than the adult, and these tiny pests gnaw at the roots of plants, which can cause infestations readily.

Thrips

Thrips are unpleasant little pests that can make leaves a yellowish or brownish colour as they suck a lot of the nutrients out while engorging on these themselves. Thrips are about 5mm long and resemble dark dots on the leaves’ upper sides.

You Should Clean Your Hydroponic System

You should ensure that you’re wearing entirely clean and preferably sterile clothing. These microscopic pests have a habit of clinging to everything on us, and we won’t know about it. So you should take time to prepare before you go looking for trouble.

Also, clean everything you take with you, including any tools you may be carrying in your hands. Make sure everything is spotless before venturing in. You certainly don’t want to bring any pests in with you, especially since you won’t be able to see them.

When you set up your hydroponic system, it’s always worth the time it takes to clean everything thoroughly. Preferably sterilise everything. All the equipment within the area will need cleaning before taking into your growing space.
The annoying thing about pests is that they can come from anywhere. They will seek a ride on anything you care to take into the growing area or tent with you.

Controlling Pests in Your Hydroponic System

You can take certain precautions when you first set up your hydroponic system, and you should practice good cleanliness right from the start. You will want to deter pests; prevention is always better than cure.

Many pests find low humidity quite attractive; fungus gnats and spider mites find low humidity especially appealing. So keep an eye on your humidity within the growing environment by ensuring at least 50% or above. Doing this alone may be enough to prevent infestations from breaking out (although there are other things you can do as well).

You should also check there is no excess moisture in the growing medium. Fungus gnats love Rockwool, so be careful if you choose that for your growing medium; otherwise, they might decide to move in.

Even if you regulate the humidity properly and carefully in this way, you may find that pests can get in. So always look for signs; don’t ever let complacency get the better of you. There are some tell-tale indicators that you have pests in your setup, so here’s what you should look out for:

You may notice discolouration in the leaves, and they may turn a yellowish or a light brownish colour. If pests cause the problem, it will likely be the pests feeding themselves on the nutrients in the leaves, which will cause them to turn that colour. Aphids are known to do this, for example. You’ll notice that the discolouration will have, at its centre, a tiny hole, which is where the mites have fed.

Some species of pests will cause spots to appear on leaves, often causing an identifiable pattern that is similar in each case. The spots may be brown, yellow, white or black, and these can be deposits on the leaves from the pest’s dung or eggs or larvae. But if you can scrape off these spots, it’s a tell-tale sign that they’ve been left by a pest or pests unknown. If you notice this, it is best to check the leaves and stems of adjacent plants immediately.

If you see what appear to be holes which may be burns or tears, it’s important to look closer. Look at the edges of these. Burns will be there because of the nearness of a light source. If this is the case, move the light source further away (you could also check your grow lights’ cooling precautions).

The holes made by pests will be tiny and sometimes slightly raised a little bit above the rest of the leaf surface. These are from the actions of the pests sucking away at the leaf as they feed themselves from its nutrients.

If any of the above occurs, you’ll want to remedy them quickly. Time is so important here. Once they become established in a hydroponic system, Pests can run through it at a devastating rate. The infestation goes from one plant to the next in a very short space of time.

You will have to decide what to do to save the situation as soon as possible. You can get rid of some pests by simply removing them or employing chemical eradication. Of course, use chemicals only as a last resort as these may cause damage to your hydroponic system.

How to Remove pests Once They are Detected

When dealing with the eradication of pests from your hydroponic system, you don’t want to damage your plants or anything else they will contact. So a ‘softly softly’ approach is always best. You can find a range of ‘natural’ solutions you can use to get rid of the pests. Ensure they are safe for your plants by reading on the container’s label; it should state openly that this is safe to use with plants.

One such solution is Pyrethrin which is quite safe to use within your hydroponic system, as even organic farmers trust it. Quite the reverse of being derived from chemical pesticides, Pyrethrin is made from the extract of certain flowers. So in this sense, it can be said to be a ‘natural’ solution.

Most people will be familiar with fly-paper, a sticky substance applied to an adhesive surface that attaches near where insects are flying or crawling. The stickiness traps the insects so that they cannot escape. These sticky traps come in a variety of shapes and sizes.
Of course, once caught in the traps, you can look at them to identify what they are if this has proved impossible before. If you suspect pests in your system, having a sticky trap or two is probably not a bad idea.
Time will usually eliminate them in this way, as they are made immobile and will not be able to breed once caught.
Give your plants a good spray every so often as a preventative measure. If pests are present, then spraying will slow down their breeding cycle and rid you of the majority of the pests.

Treatment for Getting Rid of Aphids

To get rid of the aphid pests in your hydroponics system, you first remove whole-infested plants. Then you’ll need to remove any stems and leaves which are severely infected to give your non-infected plants a chance to grow free from pests.

Certain insects are known to be good natural predators of aphids, such as lacewings (also sometimes known as ‘stink flies’ because of the horrible smell they can give off as a defensive measure), and ladybirds are not known to cause problems for plants. Soap pesticides (without harmful chemicals) are also deadly to pests but not plants.

As a preventative measure, do not overfeed the plants; the nutrition this builds up will only attract more of the little aphid pests that you don’t want around.

Treatment For Getting Rid of Whiteflies

To get rid of an infestation of whiteflies in your hydroponic system, you can first spray the plants with water then bring in some predator insects that will work for you. Lacewings and ladybirds are suitable for this.
You can also use safe organic soap pesticides (read the label to ensure they’re safe for your plants). If you wanted to, you could use Neem oil (but you should check the regulations in the U.K., where its active ingredient, Azadirachtin, is illegal, theoretically at least, though you can buy products containing Azadirachtin from retailers).

Treatment For Getting Rid of Spider Mites

To combat spider mites from a hydroponic system, you should first prune the areas with a high incidence of infestation and get rid of these stems and leaves. Then use a plant-safe (read the label) organic insecticide to deal with any remaining pests. You may want to use Neem oil every few days, which will destroy both the spider mites and their eggs.

Treatment for Getting Rid of Fungus Gnats

You can avoid the presence of fungus gnats in your hydroponic system by not overwatering the plants. But if the infestation is already there, you can allow your growing medium to become as dry as possible within two inches from the top before adding any more liquid.
To deal with the fungus gnats ‘ eggs, you can lay some sticky traps close to the growing medium. Then fight the species off by putting some nematodes in to deal with the fungus gnat larvae. If the infestation is severe, you could spray Neem oil.

Treatment For Getting Rid of Thrips

To remove an infestation of thrips in your hydroponic system, you can again use other predator species such as Anthocoridae (minute pirate bugs), ladybirds and lacewings. You could also use Pyrethrin on your plants and then spray with a plant-safe insecticide soap every few days if this becomes necessary.

In conclusion, we hope you’ve seen the importance of preventing pests from getting into your hydroponic system in the first place. Without the need for soil, it is far easier to keep these bugs out than is the case with conventional soil-based horticulture, but there is still the need to be vigilant. Vigilance is always the best means of protecting your hydroponic system from pests.

But if you’re unlucky enough to have an infestation outbreak, don’t automatically reach for the pesticides. The information above demonstrates that defeating bugs is possible by introducing other bugs, the pests’ natural predators. It’s a species-on-species battle that you can win without causing any harm to your plants whatsoever.