3 ways to use cornstarch in the garden – an invaluable ingredient for natural pest control, planting seeds, and more

I'm always amazed by the number of items in my kitchen cupboard that can be used invaluably in the garden. Take cornstarch, for example. Not only can it be used for homemade sauces, but it's also an essential ingredient in plant pest control, storing bulbs, and planting seeds. But, how exactly does this work?

You may already know about the things you clean around the house with cornstarch, but its use extends outdoors, too. It's a great addition to natural pest control methods and is useful when it comes to handling bulbs and seeds. There's no single way to use cornstarch in the garden, but each method is sure to make your gardening jobs a whole lot easier.

Here, I explore three of the best ways to use cornstarch in the garden, with tips on how to make the most of this kitchen ingredient in your yard.

3 ways to use cornstarch in the garden

These ways to use cornstarch in the garden will excite you if you already love to make homemade bug sprays or experiment with non-chemical DIYs, such as using coffee grounds for plants.

1. Use cornstarch to stop pests

If you have a problem with pests that destroy plants, turn to cornstarch to resolve the issue. More specifically, you can use cornstarch to get rid of aphids and other soft-bodied insects, including getting rid of ants.

'You can dust a light layer of cornstarch (from Walmart) on the leaves or soil where ants or beetles are active,' describes pest control expert Ed Dolshun. 'The fine powder clogs their breathing pores and dehydrates them, which is why it works.

'Of course, it is non-toxic, so it won’t harm pets or plants if used sparingly,' Ed adds.

There is a word of warning when doing this, though:

'Don’t overapply cornstarch. A heavy coating can clump when it gets wet, which could be bad for soil health or the plant’s leaves,' Ed warns. 'It can also disrupt beneficial insects if they come into contact with it, so only use it in targeted areas where you know the pest pressure is high.'

To help prevent a build-up of cornstarch, flush the leaves and soil every few days. Simply use a watering can (from Amazon) to do this

Ed Dolshun

Ed is the Catchmaster® brand’s vice president of business development and technical director, and an expert in pest control. He has over 12 years experience in the pest management industry.

2. Use cornstarch to store tubers and bulbs

Another way to use cornstarch in the garden is for storing bulbs and tubers. This is because cornstarch can be used as a drying agent, just like these silica gel packets from Amazon, which can also be used when storing bulbs.

When it comes to overwintering tender bulbs and lifting and storing tubers, they need to be kept somewhere dry. Dusting them in cornstarch will keep moisture out.

It's also a natural fungicide, so it will prevent any mold or fungal diseases from developing, helping to keep bulbs viable while in storage.

Once dusted in cornstarch, it's a good idea to keep your bulbs and tubers in breathable jute bags (like these from Amazon), and in a sheltered, dry location.

3. Use cornstarch for DIY seed tape

This final item on my list of ways to use cornstarch in the garden is a fun project to take on: you can use it as an adhesive for DIY seed tape.

Seed tape (from Amazon) is a tool that helps space seeds evenly when planting. It helps avoid seed sowing mistakes, like planting too close together, later resulting in plant roots not having sufficient room to grow.

Making your own seed tape is a sustainable gardening idea. It consists of using biodegradable paper (from Amazon) and an adhesive to stick seeds to it. You can then plant the tape and it breaks down over time, while the seeds germinate and grow.

Of course, it's ideal to use a biodegradable, non-toxic adhesive to prevent chemicals being infused into your soil. This is where cornstarch comes in.

Mix a tablespoon of cornstarch with a cup of water to make a paste. This gives you your adhesive for the seed tape.

Other ways to space your seeds include using a seed spacer dibber (from Amazon)

FAQs

Can you use cornstarch on houseplants?

Yes, cornstarch can be used on houseplants. It can be added into a mixture with water and soap to create a spray to treat powdery mildew, for example. Or, you can dust some cornstarch on plant leaves to get rid of aphids on houseplants. Just keep in mind not to overuse cornstarch on houseplants. A thick layer can hinder the health of houseplant soil and foliage. Clean houseplant leaves regularly to avoid a build-up.

When reaching for cornstarch in your kitchen cupboard, consider also using some other ingredients in the garden. For example, you can use cayenne pepper to deter squirrels, use eggshells to protect plants from slugs, and use vinegar to kill weeds.