How To Use Milk for Plants: Boost Growth, Clean Leaves & More

As gardeners, we are always looking for ways to keep our plants happy, healthy, and thriving.

We study plant guides for tips on lighting requirements, heating needs, disease prevention, bug repellants, and of course, watering needs!

Enter the spotlight: milk! Who knew that there was such a miracle liquid just sitting in our fridges!

That said, using milk to water plants is not about providing moisture. Instead, it’s about feeding them additional nutrients, repelling bugs, and promoting growth.

Using milk to fertilize our precious, hungry plants is an ancient farming technique.

Full of healthy amino acids, enzymes, sugars, and proteins, milk encourages the growth of beneficial microbes, bacteria, and fungi in our garden soil and compost heaps. 

Is milk good for plants? Milk contains calcium, vitamin B, natural sugars, and beneficial proteins that encourage growth and promote health in plants. Milk can be used as a natural fertilizer and/or pesticide. Milk can help fight against leaf viruses, aphids, and fungal diseases and is a great way to clean plant leaves. 

Is watering your plants with milk really a “thing”?

It may seem strange to consider watering your plants with the main ingredient used in your favorite cup of java, but weird or not, milk is very beneficial to our leafy friends.

You may be surprised to find that dousing your growing plants from time to time with a glass of milk is precisely what they need!

Read on to discover how milk can boost growth and promote health in your favorite green family member. 

Using Milk for Plants: What To Know First

The first thing you need to remember when trying something new with your plants is: everything in moderation! While watering your plants with milk is beneficial, too much milk can have adverse effects.

Much like over-fertilizing, drowning your plants in milk or using any type of milk in the hopes of abundant growth can result in stunted growth, wilting, black rot, and soft rot – and none of these are pleasant afflictions for you or your plants to deal with.

If you’re keen to experiment with milk,  use the below guide to using milk effectively on your plants. 

Benefits of Using Milk for Plants

The many benefits of applying milk to the plant’s foliage or directly to the soil range from providing additional nutrients for plant growth to repelling pests and fungal diseases.

To get you up to speed on what milk can actually do for your plants, check out the following benefits:

  • Milk is a source of calciumPlants need calcium for healthy growth and fruit development. Calcium deficiency in plants leads to stunted growth and undeveloped fruit.
  • Milk is a great fertilizerMilk is a source of vitamin B and protein, which promote plant health and improve crop yields.
  • Adding milk to soil prevents blossom-end rot in squash, tomatoes, and peppers.
  • Milk acts as a natural pesticide for aphids, spider mites, and thrips. These soft-bodied pests feed on the milk but cannot process it as they don’t have a pancreas and die.
  • Milk can act as an antifungal agent to prevent and combat issues such as powdery mildew. When sprayed on the foliage, the protein in the milk develops antiseptic properties when exposed to sunlight.
  • Milk promotes soil health – Milk encourages the development of healthy microbes, bacteria, and fungi in the soil.
  • Milk can prevent the growth of seasonal pathogens and deter harmful soil insects.

Basic Guidelines for Using Milk for Plants

While there are a number of beneficial uses for milk in our gardens, there are some basic guidelines we need to follow to ensure our plants receive the best possible care.

Remember what was said about moderation? Well, it’s true!

Much like reading the label and dosage instructions on medications, we can’t simply slug a gallon of milk on our plants and expect vigorous growth.

This basic guide will clarify the type of milk to use, how to use it, how often, and the precautions you should take into consideration.  

What Types of Milk To Use for Plants 

In the old days, milk was milk. It came from a cow and was enjoyed as a drink or made into butter, cheese, or cream.

As time went on, milk was pasteurized, made into ice cream, dessert treats, and milkshakes.

Nowadays, milk can come from cows, goats, sheep, camels (yes, it’s true), and even plants. And it doesn’t end there.

Milk can be skimmed, low fat, full fat, powdered, evaporated, fresh or sour. Milk selection is now a minefield, and so the question is, which milk is beneficial for plants? 

You might be surprised to find that it’s not just cow’s milk that’s beneficial to your plants.

Types of milk that can be used in the garden include:

  • Fresh cow’s milk (2%/ low fat).
  • Sour milk.
  • Evaporated.
  • Powdered milk. 
  • Buttermilk.
  • Evaporated milk.
  • Almond.
  • Soy.

Now, you can’t just add milk directly to your plant’s leaves or soil. These kinds of milk should be diluted before applying them to the foliage or soil.

Use an old spray bottle and mix equal parts milk and water before spraying onto the plant foliage or applying to the ground near the plant’s roots. 

On the topic of what not to use, it’s important to know that certain types of milks just aren’t suitable for your plants and garden. 

Do not use:

  • Flavored milk.
  • Sweetened condensed milk.
  • Skim milk.
  • Full fat (undiluted).

Not all milk is made equal, and therefore they are not all beneficial to plants. Some types of flavored milk and sweetened condensed milk are high in sugar and are highly processed too.

These will have little nutritious value for plants and may attract unwanted pests and problems.

While skim milk can promote the development of black rot and soft rot, the fat in full-fat undiluted milk can damage the plant’s foliage – so it’s really all about balance. 

How To Use Milk for Plants

Red New Guinea impatiens being sprayed with water from a mister..

Of course, you need to start with a diluted version of milk. A diluted milk solution can be applied to the plant in two ways.

You can either pour the mixture onto the soil around the plant’s roots or spray it directly onto the foliage.

Applying the milk mixture to the leaves is called foliar feeding (this article covers foliar feeding and different foliar sprays extensively).

Check the leaves after half an hour and remove excess milk residue using a moist cloth to prevent fungal disease. 

Basic Recipe

What you need:

  • Milk (cow’s milk 2% or low fat)
  • Tap water
  • Recycled spray bottle

What to do:

  • Mix equal parts milk and water (50:50 ratio).
  • Pour into the spray bottle, and shake well.
  • Apply generously to the plant foliage. 
  • Wait half an hour.
  • Remove the excess mixture with a moist cloth.

When diluting milk for the garden, the solution doesn’t have to be an exact science. Instead, simply add water to the last of your milk jug and water your plants generously. 

How Often To Use Milk for Plants

When used as a fertilizer, milk is only required once at the beginning of the growing season and again mid-season when plants are actively growing.

If using milk as a pesticide or fungal treatment, apply a milk solution to the leaves as soon as signs of disease or pest are seen. 

Precautions When Using Milk for Plants

Overwatering plants with milk can cause poor plant health. In addition to an unpleasant odor caused by the excess rotting milk, plants may experience poor growth and appear wilted.

Also, excess milk can also cause black rot and Alternaria leaf spot. 

What Plants Benefit From Milk?

Most plants benefit from the nutritional elements found in milk. However, there are specific plants that love a drink of milk.

These include the jade plant, begonia, English ivy, and African violet. A lovely milky drink also prevents powdery mildew, which seems to be a common ailment among these types of plants.

How To Clean Leaves With Milk

A woman using a soft, yellow cloth to wipe off a plant's leaves.

Cleaning the leaves of your plant with milk is much like foliar feeding.

After spraying the leaves with a diluted mixture of milk and water, allow the leaves to absorb the milk for approximately 30 minutes.

Then wipe off the excess milk with a soft, damp cloth. Cleaning the leaves with milk will also protect the leaves from unwanted pests looking for a tasty snack!

Pests such as aphids, thrips, and mealybug cannot process milk enzymes, which leads to their demise! 

Can You Put Milk on Plants?  

Applying a diluted mixture of milk and water either on the foliage or directly around the roots can boost plant health and promote growth.

This is because milk acts like a fertilizer providing additional calcium, vitamins, and proteins needed for healthy growth.

What Happens if You Water Plants With Milk? 

Milk contains calcium and vitamins and has beneficial fungicidal properties that can prevent the growth of certain bacteria and mold.

Its also thought it can help protect plants from harmful fungi that inhibit healthy growth. However, because milk contains fats and proteins, plants may have difficulty absorbing water.

Therefore, it’s best to dilute the milk with water before watering your plants with this nutritious drink. 

Do Plants Grow Faster With Milk?

When provided with the correct level of care, water, heat, and light, plants will naturally grow at their fastest. However, milk can promote healthy, vigorous growth due to its nutritional value.

Always dilute milk before applying it as a fertilizer as concentrated milk solutes can change the soil properties and restrict the plant from absorbing water. 

Is Bad Milk Good for Plants?

Milk, even if it past its expiration date, is good for plants in moderation. Apply a diluted milk soaking in early spring and again halfway through the summer.

Milk acts as a rich fertilizer providing nutrients and calcium for plants, which helps build the cells walls of plants, allowing easier absorption of nutrients and balancing the soil’s pH level. 

Is Milk Good for Azaleas?

Close-up look at an azalea stem covered in pink blooms.

Sour milk has a higher acidity level than fresh milk, making it the perfect drink for azaleas. This is because they thrive in acidic soil conditions. 

Is Milk Good for Roses?

A common fungal disease that affects roses is called blackspot or Diplocarpon rosae. Mix a diluted milk solution of equal parts water and milk and use it to spray onto the leaves.

The lactoferrin in the milk is a highly effective fungicide against this type of leaf disease. 

Can I Pour Milk on My Tomato Plants?

Milk is excellent for tomato plants. It can be used as a fertilizer and a fungicide for these prolific growers.

Tomatoes need a lot of nutrients to ensure healthy plant growth, and milk can provide an abundance of these.

Sprinkle half a cup of powdered milk directly onto the soil and water thoroughly. Repeat every other week during spring and summer.

To prevent fungal disease, mix a solution of milk and water (9 parts water to 1 part milk) and spray the foliage every three weeks in the summer. 

How To Use Milk and Molasses for Plants

Milk and molasses mixtures are hugely beneficial to plants and the soil. Molasses is a by-product created when sugar beets or sugar canes are processed into sugar.

It contains calcium, potassium, magnesium, and iron, which are excellent for improving the soil.

Use a simple solution of equal parts milk and water mixed with three tablespoons of molasses. Use this to feed plants such as peppers, tomatoes, and eggplants. This will increase their yield and flavor. 

Conclusion 

While milk may seem rather an odd choice to use on your plants, the nutritional benefits it provides are somewhat astonishing.

Aside from being nutritious for plants, it also acts as a pesticide and fungicide and can even help control weeds! 

Obviously, our plants will still need their regular watering sessions as plants cannot live on milk alone.

Watering with only milk can lead to an inability to absorb water, cause types of rot, and attract nasty soil critters.

Use a diluted milk solution mixed with a dash of molasses to water your plants during the growing season and watch how wonderfully they will grow.