Growing Organically with Compost Teas and Nutrient Mush

By Rich Hamilton
Published: December 12, 2017 | Last updated: December 12, 2017 09:59:45
Key Takeaways

Nutrient feeding “mush” and “tea” brews have been around for a while now. People that use them swear by them and will preach about them to everyone and anyone who will listen.

Just as you like your porridge and a cuppa for breakfast, your plants like some mush and compost tea for theirs.


With this style of nutrient feeding regime making a come back, let’s have a look at what these things are, what they do, how they work, and most importantly, if they work as well as people claim they do.

What is a Nutrient Mush?

Mush feeds normally come in bottle form as a super-concentrated mush paste. When you buy a bottle, there is only a small amount of thick mush at the bottom that must be diluted with water before use.


So, for example, a one-liter bottle will have enough mush in it to make up one-liter of standard concentration feed, which can then be diluted again or used as is.

For the retailer, selling these mush super concentrates is very attractive, as they are cheaper to ship to both the store and the customer. Win-win all around.

Another benefit is that the mush is not fully active until it is diluted with warm water. This means that they don’t necessarily have any extra preservative chemicals, which are sometimes added to standard nutrient concentrates to preserve or stabilize them.


A negative point with mush feeds is that because they must be diluted, the quality of the water used—be it hard, soft, medium, pure, RO, and so on—will affect the resulting solution. Some water may even have adverse effects on the overall quality of the diluted nutrient concentrate, so be mindful of what you use.

Mush nutrients are available for all growing mediums, but they work particularly well in deep water culture systems, such as bubblers as an example.


Compost Teas

In its simplest form, compost tea is what you get if you soak a porous bag of compost in a bucket of water for some length of time. The idea is that the nutrients in the compost are transferred to the water, leaving you with a liquid “tea” containing all the goodness from the fertilizer.

Making compost tea is popular, as it is relatively easy and there are countless methods and recipes available online. If you are a seasoned indoor grower, you will probably already have most of the equipment needed to make it; however, compost tea kits can easily be bought online or at gardening stores.

The good thing about DIY compost tea is that you can experiment. Try out different recipes, see what works for you, and play around to create your own super brew.

To make compost tea, you simply dilute your compost mix in water. You must also add an air line to aerate the mixture (making what is known as aerobic compost tea, or ACT for short). This makes the beneficial microorganisms—good bacteria, fungi, protozoa, and nematodes—multiply quickly, creating a rich microbial solution that enhances the soil and the plants’ immune systems.

The aeration process is key; without it, the organisms in the tea will use up all the oxygen in the water quickly and then die off. If this happens, the tea will become putrid, start to stink, and could harm your plants irreversibly.

To get the most from your tea, I would recommend brewing it with the aeration line for between three and seven days. The microbes will start to die off quickly once the air line is removed, so it is extremely important to keep the tea aerated right up until you are about to use it. Then, simply strain it and apply it.

You can buy compost tea as a dry mix or a concentrated liquid, both of which you then dilute. There are many things that can be used as the compost for these teas, ranging from animal waste to food scraps and plant matter.

Some are also more organic than others. As such, the elements that make up these mixes can vary widely. So, it’s worth noting what is in each one and what benefits that each can have for your plants before purchasing the tea that’s right for your garden.

So, why use compost tea? There are many reasons, mainly that compost tea makes the benefits of compost go further and creates a healthy balance between soil and plant.

How to Use Compost Teas

When applied as a foliar spray to the leaves, it helps to prevent foliar diseases, increases the amount of nutrients available for the plant to take up, and speeds up the breakdown of toxins. Compost tea can also increase the nutritional quality and improve the flavor of your fruits and vegetables.

Compost teas can be used either as a foliar spray or a soil drench. It can be used in all growing systems, but is best used as a foliar spray on systems that do not use a medium such as soil.

Apply compost tea whenever you spot signs of disease or undernourishment, such as wilting, failure to flower, discolored leaves, stunted growth, or small fruits. With foliar spray, it is best applied directly to the leaves at lights out, as UV radiation can have a negative effect on microbial life.

Once applied, the microbes work to overcome the problems by combating fungi and increasing soil fertility as well as providing nutrients directly to the plant. You can apply compost tea to your plants as part of your regular feeding schedule, applying liberally to the soil and leaves once every two weeks.

If you are growing edible crops, however, do not apply compost tea in the three weeks before harvest so you can be sure that you do not transfer any harmful bacteria such as E. coli to your crops through your tea.

So, there you have it: two more ways to get some extra nutrients into your plants that are well worth a try if you are looking for change or an improvement in your growing. And with all that talk of tea, why not put the kettle on for yourself too.


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Written by Rich Hamilton | Writer, Consultant, Author of The Growers Guide

Profile Picture of Rich Hamilton

Rich Hamilton has been in the hydroponics industry for more than 20 years, working originally as a general manager in a hydroponics retail outlet before becoming an account manager at Century Growsystems. He enjoys working on a daily basis with shop owners, manufacturers, distributors, and end users to develop premium products.

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