6 Effective Ways to Use Baking Soda in Your Garden (Plus 3 Myths to Avoid)

Baking soda has long been used as a natural remedy for treating a variety of gardening woes, like pests, weeds, and fungus. Unfortunately, some of these supposed treatments don’t actually work, and they may do more harm than good. In this guide, we’ll introduce you to 6 of the best ways to use baking soda in the garden, and bust through a few gardening myths about baking soda too.

What is Baking Soda?

Baking soda, or sodium bicarbonate, is essentially a type of salt that’s mined from mineral deposits. This multi-use product is often used in baking, cleaning, and deodorizing, but it has some garden uses too. The problem is, like other salts, baking soda can be damaging to plants and alter soil pH if it’s applied too liberally or used in the wrong way.

When overapplied, baking soda can cause plants to wilt, become stunted, develop leaf chlorosis or yellowing, and even die. It can also linger in the soil and make it harder for acid-loving plants to grow in the future. However, baking soda can provide major benefits to plants if you know how to apply it.

Ways to Use Baking Soda in the Garden

The important thing when using baking soda for garden purposes is to apply it in small, targeted doses and to mostly keep it away from plants you want to grow.

1. Reducing Powdery Mildew

One of the most common ways to use baking soda is for powdery mildew control. But it’s important to note that baking soda works best as a preventative or for treating small infestations of powdery mildew, and it’s less effective against advanced powdery mildew issues.

Baking soda mildew sprays work by changing the pH on plant leaves, which makes the leaves less hospitable to mildew spores. To make a foliar spray with baking soda, mix 1 ½ tablespoons of baking soda and 3 tablespoons of organic horticultural oil or vegetable oil in a gallon of water. Apply this spray to vulnerable plants in the morning when the sun isn’t high overhead, and reapply it weekly and after heavy rainfall.

2. Natural Weed Killer

In high concentrations, baking soda will kill most plants it comes in contact with, which can make it tricky to use in the garden. However, this can come in handy if you want to kill weeds without chemical pesticides.

For best results, apply baking soda only to weeds that are in areas where you’re not planning to grow plants in the near future, like sidewalk cracks. To apply, either sprinkle baking soda powder directly on the weeds or create a homemade weed killer spray with 1 ½ cups of baking soda, a squirt of dish soap, and 1 gallon of water. Rain can make these applications less effective, so make sure to apply this natural weed killer when you’re not expecting rain for a few days.

3. Fruit and Veggie Wash

No one wants dirt and grime on their homegrown produce, which is why it’s always a good idea to give garden goodies a rinse before eating. But soaking produce in water with a few teaspoons of baking soda mixed in can get fruit and veggies even cleaner and potentially remove leftover pesticide residue too. Just be sure to rinse your produce with fresh water afterwards to get rid of any leftover baking soda taste.

4. Stop Slugs and Snails

It’s a well-known fact that salt and slugs don’t mix. Baking soda is basically a type of salt, so you can use it as a salt substitute for repelling slugs and snails too.

If you want to try this trick, apply a thick ring of baking soda around the areas where you’d like to keep slugs from entering, such as around the exterior of raised beds or container gardens. Keep the baking soda ring away from your plant roots though. Applying baking soda too close to plants can potentially cause damage.

5. DIY Soil Test

Testing soil pH can tell you if your soil is alkaline or acidic and help you get a basic idea of the best type of plants to grow. An inexpensive test kit from a garden center or hardware store is a common way to find your soil's pH, but you also can conduct a simple soil test with some soil, vinegar, and baking soda.

To start, gather 1 cup of soil from a part of your garden where you’d like to test the soil pH. Then, measure 1 teaspoon of the collected soil into two separate containers and add ½ cup of vinegar to the first container. Pour enough distilled water into the second container to make the soil muddy and then add ½ cup of baking soda.

Watch the containers closely. The way the soil responds will give you an idea of whether your soil is acidic, alkaline, or neutral.

• If the container with vinegar fizzes, you have alkaline soil.
• If the container with baking soda fizzes, you have acidic soil.
• If neither container reacts, your soil pH is close to neutral.

6. Moss Control

Baking soda can also be used to eradicate unwanted moss from your lawn, patio, or back deck. However, as with weed control, it’s best to only apply baking soda in areas where you don’t intend to grow plants as it can affect soil fertility and pH.

To remove moss using the baking soda method, add 8 ounces of baking soda and 1 gallon of water to a garden sprayer. Mix and apply the spray liberally over the moss you’d like to remove and wait a few days. Once the moss turns brown or orange, rake it away.

Baking Soda Myths to Skip

Although baking soda has a lot of uses, there are a few myths about baking soda that aren't backed by any scientific evidence and can actually cause damage to your garden.

1. Myth: Baking soda enhances flowering. Some growers swear that sprinkling baking soda around flowering plants can make them bloom more. Unfortunately, there is little evidence that this works and the added salt can potentially kill your plants.
2. Myth: Baking soda is great for adjusting soil pH. Baking soda has a pH of around 9, which means it can raise soil pH. However, it’s much safer to use garden lime or wood ash for this purpose because these products won’t contribute salt to your beds.
3. Myth: Baking soda can fix smelly compost piles. While baking soda is famously good at deodorizing smelly things, adding salt to compost piles can interrupt the composting process. If you want to make compost piles smell better, aerate them and add more carbon-rich ingredients.