Worms and lime - good bedfellows?

Dear Martin

Hello from Queensland Australia. We live on the East Coast tropical side of the country.

I have been having success with my compost bin,but would like to buy some worms here at the gardening centre,but I also want to use garden lime,in the bin,to sweeten all the grass clippings,etc.

Will the worms be affected by the lime,and do a runner,or should I wait,and let it disperse?.

 We have BokChoy,Silver Beet,lettuce,Tomato,Capsicum,Chinese Cabbage,etc etc.Beans to go in,and peas.Then my garden allotment will be full,as we live in an "Over 50's" Village,and dont have much room,but the veggie gardens are elevated.

Cheers for now


Dear Brian

Hello Brian!

It’s great to hear from a gardener on the other side of the world and I’d love to come out and give you some practical help, especially with the summer we are ‘enjoying’!

It’s also pleasing to hear that your composting activities are going well and I’ll do my best to help with your two related queries.

Firstly, adding composting worms to an active heap is a good idea but you will need to make sure you don’t cook them! Adding large volumes of grass clippings and filling a bin with compostable material in one hit usually always generates high temperatures – which I would imagine is exacerbated in your climate – so it’s advisable to give some thought to the amount of material and the way you compost before introducing worms. Under the right conditions, they will happily munch their way through the material and play a big role in the process.

With regard to garden lime, it’s something that I wouldn’t recommend adding to a compost heap. The thinking behind the introduction of lime is that the material in a heap can become acidic during the process and whilst the PH level is likely to drop slightly during the initial and secondary degradation and conversion phases, the maturation part of composting tends to see a return to neutral conditions; rather technical but a good explanation!

There is also some evidence that lime and lime-based products can be harmful to many of the bacteria which play an essential role in the composting heap and I’d recommend that instead of adding lime to the composting process, add it to the soil when using the compost.

I hope this information proves to be of some help; your raised bed vegetable garden set-up sounds fantastic and I hope your efforts are rewarded with bumper crops.

Many thanks once again for your enquiry and please don’t hesitate to contact me should you require any further information.