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Plant Aid with Aaron

How to treat scale on houseplants

Episode one of Plant First Aid with Aaron Deacon

In this first episode of a series we’re calling Plant First Aid, our favourite plant and soil expert Aaron Deacon of BIOS Nutrients takes on… scale in houseplants! In his typically expert fashion, Aaron takes through: what scale is in the first place, how to identify a scale issue on your indoor plants, and how to get rid of it (whew!).

If you’ve discovered scale on one (or more, yikes) of your houseplants, this episode will help you. Aaron even includes a recipe for a powerful insecticidal soap that you can mix up with ingredients you’ll likely have on hand in your kitchen. Easy.

And if you need more help – we’ve been there – you can now book your very own private consultation with Aaron. He can walk you through easy, effective solutions to your indoor plant problems. If you don’t have a problem but need some general houseplant advice, Aaron can help you with that, too.

What is scale on houseplants?

Scale on houseplants refers to a common type of insect pest that can infest indoor plants. There are approximately 8,000 different types of scale. Scale insects are tiny, oval-shaped or round-shaped insects that attach to the stems, leaves and other parts of indoor and outdoor plants. Scale insects feed on the lifeblood of your plant – its sap. Wretched!

As mentioned, scale insects are tiny (about the size of the head of a pin), and they also vary in colour. They may be white, black, orange, or a camouflage colour that blends in with the colour of the leaf or stem the insect has chosen as its habitat. This, obviously, can make it exceptionally tricky to spot scale insects on your plant. We empathize, trust us.

There are two types of scale insects. Soft scale is encased in a protective waxy coating and is most often the type that will affect houseplants. Soft scale, fortunately, is relatively easier to eliminate than its brethren, armored scale. Armored scale, as indicated by its name, secretes a hard shell overtop its body to protect it from predators (and anxious plant parents) – making it tougher to kill.

Our video focuses mainly on soft scale, as that type of scale insect is the pest that’s usually found troubling houseplants. If you need help with armored scale, this article will be of use in your efforts. Our earnest wishes for the best of luck dealing with this pest.

How to identify scale on houseplants

We know! We mentioned above that it can be hard to identify a scale insect problem on your indoor plants, because the bugs are a) tiny and b) sometimes deploy camouflage to become virtually invisible on your plants. That being said, there are signs to look for to identify a scale infestation.

Top three signs of scale in houseplants

The number one sign of scale in houseplants is…scale! Although individual insects can be hard to spot, they actually often gather in clusters on the plant. So, inspect your plant thoroughly for clusters of very small shell-like bumps on the leaves, stems or other areas. The clusters can be quite small, but they can also be as large as a pencil eraser. In other words, get out your magnifying glass, just in case. Look for groups of oval-shaped or round-shaped insects with a waxy coating.

Next up – examine your plant carefully for a sticky, whitish, waxy substance (as Aaron describes in the video). This is the sugary secretion that scale insects release after feeding on your plant. We know – yuck! Unfortunately, this sugary secretion can also be a lovely habitat for fungi and bacteria which can compound a scale insect problem.

And third, check for leaf discolouration or damage. You may find yellowing or curling leaves, especially of younger stems and leaves – young leaves are rich in plant energy, a great food source for scale insects.

How to treat scale on houseplants

Step One

Your first task in treating scale on houseplants is to remove the adult insects. Because these insects quite firmly attach themselves to plants, you’ll unfortunately need to spend time manually un-sticking them.

Use a soft brush (a small paintbrush can be effective) or cotton swab dipped in alcohol to sweep the bugs off of your plant. Take care to remove all of the visible scales, as even a few left behind can create a new infestation.

Step Two

Mix up a powerful insecticidal soap, using Aaron’s all-natural recipe. He includes it in the video, but here it is again, for ease:

Aaron Deacon’s insecticidal soap recipe
½ TBSP olive oil (or other vegetable oil)
2 drops of castile or natural liquid soap
1 TBSP diatomaceous earth
.25 mL yucca extract
1 L (4 cups) distilled or filtered water (not tap)

1. Use an immersion blender or shake in a sealed container to blend until thoroughly mixed (no visible drops of separated oil)
2. Pour into a spray bottle

Note: as Aaron mentions, if you don’t have diatomaceous earth or yucca extract on hand, don’t worry. The oil, soap and water combination is still extremely effective.

Step Three

Using your spray bottle of insecticidal soap, spray the tops, undersides and stems of your plant’s leaves, as well as every other part of the plant. Be sure to thoroughly cover the entire plant.

Allow the mixture to dry on your plant.

Repeat this treatment once every two days for a week to disrupt the life cycle of the insects and prevent future infestations. And make sure to remove any adult bugs you find as soon as you see them.

A final note of caution about scale on houseplants

As with any pest concern, it’s really important to get ahead of the problem before it spreads to other plants, or creates an insurmountable problem generally.

Scale presents its own particular concerns. Adult female scale insects lay their eggs beneath their bodies – up to 2,000 eggs at a time. We don’t need to tell you how this can quickly turn into a serious issue for your houseplant population. We won’t say any more! (We know you know.)

Consult with Aaron

If you’d like to book a private consultation with Aaron, click on over to this page to get started. And get some answers to your plant questions! Or, if what you need is just some really friendly, helpful advice – you can get that, too, from our absolute favourite plant and soil expert.

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