Top tips for worm farmers
Top tips cheat sheet...
We have put our top tips into one page that you can stick on the fridge - a quick reminder of what food goes in, what food doesn't and the hot topics for every worm farmer.
Download the Top Tips now and keep it handy!
Paper, cardboard, and more paper.
It is good practice to match the volume of food scraps [nitrogen] with shredded non-shiny paper and cardboard [carbon]. Rip up old envelopes, receipts, toilet rolls, egg cartons, and non-glossy advertising materials and add to the scraps in your kitchen, as well as adding shredded newspaper and cardboard to your worm farm.
You can also use old straw, dried leaves and rotted lawn clippings as a source of carbon. We recommend adding equal amounts of carbon to nitrogen.
When in doubt add more paper!
If you add more food than the worms can eat it may go rancid and create a toxic, smelly environment.
As a rule of thumb, add food when about half of the previous feed has been eaten, and spread it out in a layer of no more than 50mm thick.
Cutting up food will allow the worms to break it down quickly before it starts to rot, which will in turn avoid any smells.
Keep it cool
Worms will perish if overheated, so it is important to keep your worm farm out of the sun.
Make sure your worm farm is always out of the sun, preferably in deep shade. In a garage or under the house is perfect as the temperature is more regulated.
On hot days - over 30 degrees - freeze a bottle of water and bury it deep in your worm farm to create a cool zone. Replace the bottle as it defrosts.
Cover with a thick layer of wet newspaper inside the bin, and a wet blanket or towel on the outside to create a cooler micro climate.
If you know there are hot days ahead, don't put a lot of food scraps in - the activity of processing food creates heat and may add to the problem.
Keep an eye on them – if the worms are massing in one spot or trying to escape it can be a sign they are suffering heat stress.
Fluff it real good
Worms need to breathe, so let the oxygen flow. Give the top few inches of your farm a fluff up every now and then with a fork to let the air in.
Adding paper and cardboard also keeps the feed layer open and airy.
The Hungry Bin
Assembling the Hungry Bin
There are really clear, step by step instructions included with the Hungry Bin. It mostly just clicks together, and then you screw on the wheels so no construction experience necessary!
Have a look at the video [left] and download the instructions for more information.
TIP : Use a hammer to tap the clips that hold the castings tray in place, they need to click firmly into place to hold the weight of the bedding you will be putting in.
What else will I need to setup the Hungry Bin
The Hungry Bin is a continuous system – food in the top, liquid and solid castings out the bottom. To get the bin started you need to fill in the middle…
3 x 30 litre bags of compost or potting mix goes into the Hungry Bin to start it off. Or if you are transitioning from another worm farm, use the castings from that farm and make up the volume – you need to fill the Hungry Bin to about 75% full.
The first few harvests of castings will be made up of the initial bedding you put in, but it will have had liquid castings flowing through it so will be greatly improved.
You will also need worms – surprise! Again, you can transition from another worm farm or purchase them with your Hungry Bin. We suggest at least 2000 worms to start with, or you can speed up the process with 4000 or more.
How long before I can harvest liquid and castings?
You are harnessing a natural process by using worms to turn your waste into gardening gold.
The worms take time to acclimatise, multiply and grow bigger before they are functioning at full capacity. This process takes some months, and over that time you can monitor them and slowly increase the amount of food you give them.
We have created a timeline of what to expect and how to manage the worms as they get up to speed. Stick it on your fridge as a reminder!
Harvesting the worm juice
The liquid [vermicast] comes straight through the Hungry Bin and into the tray that sits under the bin. You don’t have to remove the casting tray which is clipped onto the bin, or really do anything at all!
If you are concerned about kids or animals getting into the liquid, or if you are finding it is evaporating, replace the tray with a small bucket or plastic jug.
You can use the worm juice as soon as it appears in your tray or bucket. Whilst there is no harm in putting it straight onto plants as is, you can dilute the worm juice 1:10 to make it go further. If the liquid smells, pour it back through the worm farm to process it further and remove the smell.
Worm juice is safe for vegetables, fruit trees, and flowering plants. Apply it to the soil, or spray on the leaves as a foliar feed.
Harvesting the worm castings
The worm castings build up slowly as the worms eat their way through your food scraps. It will depend how much food they are processing as to how regularly you will harvest castings. Check after 12 weeks when you first start, then around every 8 weeks when they are being fed regularly.
The castings are harvested by unclipping the tray at the bottom of the Hungry Bin. When they are ready to harvest they drop into the tray; if it is empty they are not ready yet…
Due to the great design of the Hungry Bin, there should not be many worms in the tray when you remove it as they will stay close to the top where the food is. It is an easy task to pick any wayward worms out and drop them back in the bin.
Use the castings as you would dynamic lifter - it can be mixed with potting mix, spread around your plants as a top dressing or dug into the top layer of a garden bed before planting.
Feeding and worm care
What do I feed my worms?
Worms can eat most things you can eat, with a few exceptions. We have put a list together of what to feed [and not feed] your worms in our top tips PDF.
Food scraps, aged lawn clippings, manures, teabags, coffee grounds, and vacuum cleaner dust – almost anything organic.
Chopping your food scraps finely will speed up the process and avoid food rotting before the worms have a chance to eat it. Finely chop egg shells, or dry them in the oven and crush to a powder – these will help balance the acidity in the bin. Crushed egg shells also add grit to the worm farm which helps the worms digestion.
Shredded paper and cardboard, egg cartons, ripped up newspaper, receipts and envelopes should all be a regular part of the worms diet. LOTS of non-glossy paper should go in your worm farm.
Spread food out over the surface when you add it, up to 50mm thick – piles of food or thick layers can putrefy before the worms eat it and will create a toxic environment in the farm.
See also What do I NOT feed my worms, and Do I need to add anything other than food scraps? below for more important info.
What do I NOT feed my worms?
Outlined below are the foods you should not put in your worm farm - some are bad for the worms’ stomachs, or they may just avoid them leaving them to rot, which may cause smells.
Dairy - yoghurt, cheese, milks
Bread, rice, pasta, processed foods - you can add the odd crust or bits of cooked rice off the dinner plate, but don't add lots of starchy foods. Worms don't like them and they may go off or attract pests.
Animal products - bones, meat, fish, shellfish
Acidic foods - citrus, pineapple, garlic and onions.
Spicy foods - worms are plain eaters, and don’t like spicy food such as chillies, chives, curries etc.
Oils - won't be processed by the worms so may cause smells or an unfriendly environment
Chemicals - avoid any materials contaminated with toxic chemicals, such as sawdust from treated wood, paper towel used with cleaning sprays, disinfectant wipes etc.
Worms love coffee grounds but mix them with other foods and paper. Large amounts can emit ammonium, so if you have a big quantities allow it to dry out and age first.
The same advice applies if you want to add chicken manure – it is high in nitrogen and needs to age first to blow off the excess ammonium.
Do I need to add anything other than food scraps?
The carbon to nitrogen ratio in your worm farm is important – food scraps are high in nitrogen, so need to be balanced up with carbon such as paper, cardboard or dry leaves.
Paper and cardboard are a great cure all in the worm farm. Regularly add shredded paper and cardboard – an equal amount by weight to the food scraps you are adding – to keep the carbon content up and the mix in your farm light and airy.
Rockdust adds minerals that plants need that won't come from other food sources, and will make your worm castings a more balanced soil conditioner.
Eggshells are a great source of calcium, but are hard for worms to eat so crush them finely – you can put your eggshells in the oven or on the windowsill to dry them out, then crush into a fine powder to use on your worm farm.
Lime powder helps to balance your farm - food scraps are acidic, and lime is alkaline [and will add calcium]. Sold at garden centres, adding one dessert spoon of lime if you see signs of acidity will help keep the Hungry Bin on an even keel.
How much can I feed my worms?
Overfeeding worms is a common mistake, particularly when the worm farm is new. A useful rule of thumb is to add more food when half of the previous amount is gone.
Spread food out over the surface when you add it, around 50mm maximum – piles of food or thick layers can go off before the worms eat it and will create a smelly, toxic environment in the farm.
The worm population will grow to meet the amount of food available, so regular feeding will keep your bin functioning well. They are not binge eaters, so can’t handle large amounts of food every now and then.
Do I need to add water?
As there is a lot of water in food scraps you should not have to add water very often. However you can sprinkle water over the bed from time to time to flush more worm juice through, or if there are signs of it being a bit too dry.
In hot weather you may want to sprinkle with water to help regulate the heat, and make sure the contents don’t dry out
If you have a worm blanket – paper, old blanket, underlay – keep it damp but not wet in hot weather. It is also good practice to moisten cardboard and paper with water when you add it.
Can I add garden waste to the worm farm?
Yes! You can add dry grass clippings and deciduous leaves to your worm farm, as long as you keep food scraps and dry waste balanced.
Avoid adding fresh lawn clippings, evergreen or native leaves, and sticks or woody stems.
Can I add cat or dog poo to the worm farm?
Cat and dog poo can contain diseases, and for this reason it is better to create a separate worm farm specifically for this purpose. It is also advised to position an animal poo worm farm away from human activity.
Worms will eat dog and cat faeces but if given a mixed diet tend to prefer the food scraps – another reason to set up a separate smaller farm.
Do I need a worm blanket?
Worms are surface feeders and feel safer if under some cover. They will also be more inclined to swarm all over the food if covered rather than just access it from underneath.
You can buy a commercial worm blanket, or use cardboard, newspaper, carpet, underlay or similar. Keep it damp but not wet in warm weather to help manage heat in the worm farm.
If using old carpet or underlay, clean it thoroughly to make sure there are no toxins before putting on your worm farm.
My worm farm smells...
A properly functioning worm farm should never smell, apart from a very nice sweet smell of soil. If you notice a bad smell it is most likely from rotting food – the worm farm is becoming anaerobic, and releasing nasty gasses. There is a deficiency of oxygen which the worms and healthy composting bacteria require.
When there is more food than the worms can eat, it starts to rot. Do not add any more food scraps until the smell disappears and your worm farm is back in balance. Keep the layers of food scraps no more than 50mm thick and always mix in lots carbon matter.
Get lots of air into the system by “fluffing” in shredded cardboard, newspaper, dried mulched straw or leaves.
Cutting up large chunks of food so that the worms can break it down more quickly will ensure the food doesn't have time to rot before they can eat it.
The worm juice smells...
If the liquid coming out of your worm farm smells bad, don’t use it on your plants! The smell is coming from putrefying organic matter that has not been broken down properly, and has gone anaerobic. This liquid may contain phenols, alcohol and phytotoxins, which can be damage or kill your plants. This is a common problem with cheaper worm farms that do not hold a deep layer of mature castings, which you need to “finish” the worm juice properly.
Properly finished worm juice should never smell apart from a nice earthy sweet smell, and can be stored without smelling or going off.
If the worm juice smells you can add it slowly back into the Hungry Bin to filter the liquid back through the castings.
The level has dropped....
Over time the level Hungry Bin can drop down, but is easily fixed. Using finished compost or potting mix add it in each time you feed the worms OR take out the top layer of food and worms and add in enough potting mix or compost to bring the level back up.
The main thing is don't completely bury the food in the worm farm, it needs to stay near the top with the worms.
It is also advised not to take the castings tray off the bottom if the Hungry Bin is not filled to its working height as your contents may all fall through - the design requires a full bin to compress the castings and allow you to take the bottom tray off.
The worms are crawling all over the lid....
The worms will travel around the bin including over the lid. It is not a sign of a problem unless they are massed in a ball, which means they are stressed. There are a few things that can make the worms travel more than usual.
If it is very humid, or if the worms sense it is going to rain they may move to 'higher ground', which in a worm farm is the lid and sides. Once the rain passes they will move back into the bedding.
If your worm farm is out of balance, the worms may be trying to migrate. If it is too acidic, too wet or dry, too hot – these can all be reasons for worms to want to move house.
A well balanced bin does not have a strong smell, is damp but not wet, is not sludgy or dry. Identify any potential issues, and check through the other FAQs for solutions to your problem.
Tiny flies and other visitors...
Keep in mind worm farming is an organic process, and other insects will be attracted to that system. You may find vinegar flies, mites, tiny white worms (pot worms) and other creatures in your farm from time to time – they will appear and disappear at different stages, and most do not create problems.
Many of these insects like acidic conditions, so sprinkling lime or dolomite over the bed will make the environment less attractive. Yet again regularly adding plenty of paper - which is alkaline - means you can avoid these issues.
Small flies such as fruit flies and vinegar flies will naturally be attracted to the food. If they are unwanted simply bury any fresh food under a layer of paper or add a layer of soil over any exposed food.
Slaters, ants and earwigs are fairly harmless, but are more likely to appear if the bin is dry. Sprinkle with water, and put a thick layer of damp paper over the surface to deter large infestations.
Maggots are an indication that there is meat or protein in the worm farm, which is why we suggest not adding these in your feed. Do not panic as maggots are actually good composters and will break down food and add nutrients to castings in much the same way as worms – and they will turn into flies eventually and fly away!
An easy remedy is putting a layer of wet newspaper, old carpet or hessian, or a layer of soil over the food which will ensure the worms can still access the food but other insects are blocked out.
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