Best compost starters

Fertilizers

The right balance of browns and greens is necessary to keep an outdoor compost bin odor-free and flourishing.

BestReviews is reader-supported and may earn an affiliate commission. Details.

Which compost starter is best?

Globally, food waste contributes 8%-10% of all greenhouse gas emissions. One way to mitigate food waste in your home is to start a home compost bin, which not only keeps compostable materials like food and yard waste out of landfills, but also enriches soil and reduces the need for fertilizers. Home composting might not be for everyone, but it’s a great way to combat food waste in your home and provide rich soil for your garden. 

Compost starters contain beneficial bacteria and nitrogen to kick-start your compost pile and reduce odors. The Biomaster Compost-It Compost Accelerator is an organic compost starter that uses over 60 different microbe strains.

What to know before you buy a compost starter

Home composting

Many areas now have municipal or private composting companies as an option, but the advantages of home composting stand out if you’re a gardener. You can even start a home compost bin in the kitchen. With the right balance of microbes and nutrients, indoor compost won’t have too strong of an odor. 

Benefits of a compost starter

Compost relies on a mixture of organic materials decomposing over time to create a rich, fertile mixture that improves garden health and yield. Having the right mixture of waste to get the process started can be a difficult prospect for a home compost pile. Compost starters speed up the process and are particularly helpful for those in colder climates.

How to use a compost starter

Most compost starters are relatively straightforward and easy to use. Check the packaging for the required amount of starter for your compost pile, and then sprinkle the starter on. Many require that you then mix or fold it into the compost so the microbes and bacteria can get to work. 

What to look for in a quality compost starter

Ingredients

Different brands of compost starter often have a different blend of microbes, nutrients and materials that work to move the decomposition process along and control odor. Some contain different ingredients to cause the same effect, from chemical formulations to animal products. Stronger formulations work more quickly and require less product to be used. If an ingredient list is available, you can peruse it to see how well it suits your needs.

Scent control 

Those with a large compost bin that’s situated far away from the house may worry less about scent control, but for many, it’s a prime worry when starting a compost bin. Some starters focus more on scent control than others, so always check reviews if that’s a priority for you. In general, those that work more quickly and have more active microbes in them are more effective at scent control. Some also highlight this aspect of the product. 

Environmental impact

Most compost starters are environmentally friendly and on the natural side of things, for obvious reasons, but if a truly organic garden is important to you, look for a compost starter that’s certified organic or certified for organic use. However, all compost starters are made of garden-safe materials.

How much you can expect to spend on a compost starter

Compost starters aren’t the cheapest gardening product on the market. Generally, you can expect to spend $12-$25 on a compost starter. 

Compost starter FAQ

Will a home compost bin smell bad?

A. It’s unavoidable that decomposing organic material will emit an odor, but the odor can be minimized. Particularly with the aid of compost starters or accelerators, the smell can be kept under control for a relatively pleasant composting experience.

Are compost starters safe for worm bins?

A. Most starters are safe for use with worms or insects, but not all. If you plan on using your starter in a worm bin or insect farm, look carefully at the ingredients to make sure there’s nothing that could potentially hurt them. It’s also smart to test the starter on a small portion of your compost first before introducing it to the general population.

What’s the best compost starter to buy?

Top compost starter

Biomaster Compost-It Compost Accelerator

Biomaster Compost-It Compost Accelerator

What you need to know: A top-rated organic compost starter that works for small kitchen compost bins as well as it does for big yard piles.

What you’ll love: It comes in an easy to use package with a spout for sprinkling, contains over 60 different microbes and is able to be used on all kinds of compost, including worm and insect bins. It’s one of the fastest-acting compost accelerators on the market.

What you should consider: At 100 grams, the bag is on the small side, and it’s not the cheapest. There’s no ingredient list available online.

Where to buy: Sold by Amazon

Top compost starter for the money

Jobe’s Organics Compost Starter Microbe Additive

Jobe’s Organics Compost Starter Microbe Additive

What you need to know: A solid, affordable option from a trusted gardening supply brand.

What you’ll love: It works quickly; most users saw results in 2-3 weeks. It’s one of the less pricey options. Contains Jobe’s Biozome, a trademarked blend of microbes, fungi and archaea.

What you should consider: It requires more starter than some other mixtures to get the desired effect, and it isn’t the most effective at odor control.

Where to buy: Sold by Amazon

Worth checking out

Roebic Compost Accelerator

Roebic Compost Accelerator

What you need to know: A reliable and effective compost accelerator that works for most waste.

What you’ll love: Users were pleased with the strength of the product. Most found it easy to use. It’s also pH-balanced, meaning it’s incredibly effective at keeping the smell down.

What you should consider: It won’t work on all materials, and it doesn’t seem to have microbes added to it, rather, it’s a mixture of limestone, silica and urea.

Where to buy: Sold by Amazon

Sign up here to receive the BestReviews weekly newsletter for useful advice on new products and noteworthy deals.

Arabella Matthews writes for BestReviews. BestReviews has helped millions of consumers simplify their purchasing decisions, saving them time and money.

Copyright 2021 BestReviews, a Nexstar company. All rights reserved.