*Please note a limit of 2 bags per order due to shipping weight before overweight shipping applies* *You can order more than 2 bags and I'll be touch to arrange payment if overweight shipping is needed (rates are here). I'll try to get you standard rates if I can. This product counts towards the heavy bag limit, so if combining with other heavy products there's a limit of 2 heavy products total (eg: 1 potting mix 5 litre + 1 gnat barrier). What is Gnat Barrier? Yates Gnat Barrier comes in a 4.5 litre bag, and creates an abrasive, physical layer that prevents annoying Fungus Gnats from landing and laying eggs in your indoor pot plants. Gnat Barrier is natural and non-toxic, made from abrasive pumice granules, making it a safer and more effective alternative to using diatomaceous earth. How do you use Gnat Barrier? Simply sprinkle a layer of the granules over the surface of your pots to create a barrier against Fungus Gnats. Because Gnat Barrier is made of pumice, not diatomaceous earth, you can water through Gnat Barrier with no need to reapply after every watering. Check your layer is at least 3cms deep and covering the surface of the potting mix completely. Water gently straight after applying to settle the granules in and check you've got no gaps. Over time the granules will slowly settle, so top up when the layer becomes less than 3cms deep. Best used in conjunction with Mozzie Bits to kill the larvae, and a Sticky Trap on top of the granules to trap adult flying gnats. Keep using Gnat Barrier to stop them coming back. How many pots will 1 bag of Gnat Barrier cover? Based on the recommended 3cm deep covering, one 4.5 litre bag of Yates Gnat Barrier covers about 10 x 13cm wide pots (more if smaller pots, fewer if larger), so it does depend on your pot size. For the fastest results, use Gnat Barrier along with Mozzie Bits and Sticky Traps (above). What's wrong with diatomaceous earth? Diatomaceous Earth isn't earth at all, but actually fossilized remains of tiny, aquatic organisms like plankton. It's often recommended for the same purpose at Gnat Barrier, to create a barrier to deter Fungus Gnats. However diatomaceous earth is a little controversial when used inside the home, or for indoor plants. Diatomaceous earth (DE) is toxic to mammals unless you find a food grade source. Not great for kids or pets. DE is fine, glass like particles. When dry, which DE needs to be to work, it is like a fluffy powder that easily becomes airborne. Aside from the health risks, DE doesn't work when wet, so needs to be reapplied every time you water. If you do use diatomaceous earth, keep doors and windows closed so it doesn't become airborne when dry, reapply after watering, and keep pets and kids well away. Gnat Barrier, made of natural, non-toxic pumice granules, is a safer alternative that's also more effective for use indoors.