Is Baking Soda Good For Plants? How to Use it Safely and Effectively

Gardening lore is full of testimonials about using household products to solve problems with your plants. While baking soda is often touted as an easy DIY aid for your plants, it isn’t a cure-all and needs to be used carefully so it won’t do more harm than good.

That doesn’t necessarily mean using it correctly won’t work, but there are some limitations to what baking soda can do. Here we explore some ways baking soda can be beneficial for your plants, and some ways that it’s not.

Is Baking Soda Good for Plants?

Chemically speaking, baking soda is a salt defined as sodium bicarbonate. While some types of salts can be beneficial to plants, sodium bicarbonate is not on the preferred list.

Baking soda has a drying effect and it is non-selective, meaning it can kill any plant it comes into contact with, including your lawn, flowers, and vegetables, if used incorrectly.

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4 Ways to Use Baking Soda in Your Garden

Kill Weeds

Baking soda, in combination with soap and water, can help eliminate small weeds. Cover and protect lawn grass, ornamentals, and edible plants when using it in a spray. Apply weekly to prevent weeds from growing back.

To make a spray solution mix 1 1/2 cups of baking soda and a small amount of liquid soap in one gallon of water. To use the powder method, sprinkle baking soda directly on weeds on a hot (upwards of 85°F) day. The sprinkle method only works if it doesn’t rain for three or four days following application.

Deter Pests

Sprinkling salt on slugs and snails causes them to dry up and die—and baking soda can do just the trick as well. For a more effective (and less time-consuming) option, try leaving baking soda out for these pests to consume rather than sprinkling it on them.

Mixing baking soda and sugar in a small dish and place it near vulnerable plants. Soft-bodied insects, like caterpillars, slugs, and snails may be attracted to the sugar, consume the baking soda, dry up, and die.

More Blooms on Flowers

A handful of ornamentals prefer alkaline soil. Garden anecdotes claim sprinkling baking soda around the base of flowers like geraniums, coneflowers, daylilies, and clematis encourages more blooms.

A few teaspoons of baking soda can be mixed with a liter of water and sprayed on other ornamentals, like hydrangeas and lilacs, that thrive in alkaline environments.

Use this method only with ornamental plants that prefer alkaline soil. Use it sparingly to avoid impacting other nearby plants and grasses that can be damaged by a high pH level.

Control Fungal Infection

A baking soda formula won’t eliminate the spores that cause fungal infections like powdery mildew, but it can control the symptoms when combined in a spray with water and horticultural oil or soap.

Mix one teaspoon of baking soda and one teaspoon of horticultural oil or liquid soap in one gallon of water. Spray infected foliage covering it completely including the undersides of leaves. Repeat weekly or every two weeks as needed.

Risks of Using Baking Soda For Plants

Baking soda adds salt into the soil, raising alkalinity to a level too high for most plants. High pH can block the roots from taking up other important soil nutrients needed for optimum health. Overuse can cause plants to wilt, dry up and die.

5 Things to Add to Plants to Support Them

Well-rotted compost is the best organic remedy for supporting strong, healthy plants. It won’t repel pests, but when added to soil, can supply plenty of nutrients and micronutrients. It can improve drainage, add nutrients, balance pH levels and it costs nothing more than a little labor on your part.

Some items listed below contain micronutrients good for plants. Always do a soil test to see if yours is lacking the nutrient you hope to boost. Too much can cause an imbalance that may harm the plant.

Epsom Salt

Epsom salt can boost magnesium content and lower soil pH. Signs of magnesium deficiency include yellowing between leaf veins and early leaf drop. A soil test is recommended since too much magnesium can block calcium uptake.

Coffee Grounds

Coffee grounds contain a number of micronutrients and trace elements. It breaks down easily and is a good addition to the compost bin.

This is an all-around safe amendment but works best if composted first. Too much added directly to soil can adversely affect nitrogen uptake. Coffee grounds also kill slugs.

Eggshells

Eggshells add minerals calcium carbonate, potassium, and phosphorus to soil which are primary and secondary nutrients. They do not break down easily and are most effective when crushed and added to the compost pile.

Wood Ash

Wood ash can contain a number of trace elements plants can use. It also raises the pH level making soil less acidic and more alkaline. Wood ash should not be used around plants that require an acidic pH. Test soil before applying it in your gardens.

Hot Peppers

A combination of hot peppers and water with a small amount of oil can ward off many animals and insect pests. Cayenne peppers work well but other hot peppers with a high Scoville rating are also effective. Use fresh or dried peppers, flakes, or powder added to a gallon of water with a few drops of oil.

This is a repellent that doesn’t necessarily kill pests but discourages them from devouring your plants. It also must be reapplied after rain.