Monthly Archives: August 2015

The Biggest Natural Pests and Threats for Indoor and Hydroponic Plants

When you grow plants indoors and especially using hydroponics, you will find that your plants are naturally at far less risk of pests and insects as compared with growing them outdoors. Slugs are no longer a threat and the same is true for caterpillars to some extent.

However this does not mean that your indoor plants are going to be completely safe and there are still a number of different pests that can wreak a lot of damage should you let them. Here we will look at some of the most common culprits when it comes to your indoor gardening.

Common Plant Pests


Plant pestsAphids are the first pest that will spring to mind for many people when it comes to indoor gardening and for good reason. These little critters are highly common, easy to see and unfortunately not very easy to control. They can be any color and will often appear on the underside of leaves clustered into a group. If the problem gets bad, then you might even notice a sticky honeydew appearing on the plant.

The best natural treatment for aphids is ladybirds. Of course you may not want to fill your home with ladybirds either though, so an alternative is to use pesticides containing malathion or diazinon.

Spider Mites

Spider mites are almost invisible and often only visible with a magnifying glass – a good reason to occasionally check your plants.

A sign that you might have spider mites is that the plant begins losing its normal green color. It may then look bronzed or somewhat washed out and there may also be a fine webbing covering the undersides of the leaves. Controlling mites is difficult and you should isolate the plant at the first sign of infestation. Spray it weekly with an insecticide soap – or even regular water and soap. Be vigorous as the mites can reproduce once every 3-7 days. Spider mites aren’t insects so insecticides don’t always work.

Scale Insects

Scale insects too often go unnoticed allowing them to build up in number. They are oval, brown and look a little like limpets with slight shells. The shells protect them against pesticides but they can be killed by dousing with alcohol using a cotton bud.


Mealybugs look like white bunches of cotton or fluff and can be mistaken for diseases. They are often found on the undersides of leaves, on stems or at the base of leaf joints. The best way to kill them is with a little alcohol – so dip a Q-tip into some and then dab a little on the affected area.


The whitefly is so named as adults will look literally like white flies. These are larger than many of the other pests on this list which makes them unsightly and unfortunately they can fly and so travel between plants. This also makes them very hard to kill with insecticide. Kill off the adults manually if you can and then use insecticidal soap to remove any infants.

Soil Insects

Soil insects live in the soil and may be seen burrowing when you go to water your plants. The adults can crawl or fly around on the surface of the plant but they don’t actually do much harm. In large quantities they may cause wilting in which case drenching the soil with insecticidal soap can often provide a solution. Of course you don’t need to worry about soil insects if you use hydroponic gardening.


Thrips are light brown and slender insects that look a little like weevils. They’re quite unpleasant when seen but are hard to spot as they’re very small. They distort leaves though through a process called ‘rasping’ and this can leave behind scars. Spray with insecticidal soap.


Ants don’t directly harm plants but in fact ‘farm’ for honeydew using mealybugs and aphids. In large quantities though they can damage root systems by borrowing into the soil. Again, insecticidal soap drenched into the soil will normally provide a solution. Having lots of ants on a plant is often a sign that the plant isn’t healthy though and it may have other problems.

Spraying flowersTips for Preventing Pests

Using the above information you should be able to identify and combat specific types of infestations affecting your plants. Meanwhile though, there are also some more general tips you can use to prevent the majority of infestations before they occur and to prevent the spread of insects.

The first tip is to make sure you always use clean pots and planters when you re-pot a plant and that you use sterile potting soil wherever possible. Using garden soil can risk bringing in all kinds of insects.

If you have a new plant, then you should isolate it for about a month while looking for signs of infection or disease. This is especially important if the plant came from a garden center where it could very easily pick up problems – just as children pick up knits from kindergarten. The same also goes for plants that you might have kept outside temporarily during summer. Isolation prevents any problems that one plant has from spreading to the other plants you own – and so of course it’s also a good idea to move plants as soon as you notice signs of an infestation.

Another tip is to occasionally ‘bath’ your plant. A little soapy water and a soft cloth can help you prevent a surprising number of problems. This also gives you a great opportunity to examine your plant. Remember that some pests can only be seen under a magnifying glass, so take a closer look!

Finally, make sure to generally look after your plant and to keep it healthy. Like humans, plants are less likely to get ill if their natural defenses are high. Regularly feeding your plant, watering it and giving it plenty of light are all things that can help it to thrive and thus reduce the chances of it becoming ill.

Stay vigilant, keep some pesticide to hand and act quickly. Follow these three rules and you should find that pests are rarely a problem for your indoor gardening!