You've picked your soil bnow what goes into it? Amendments are the bits you mix through your medium to tune drainage and feeding, and getting two or three of them right is the difference between roots that breathe and a pot that sits like a swamp. Here's what each amendment actually does, how much to add, and what we stock alongside the soil so you can sort it in one trip.
What does perlite do in soil?
Perlite is volcanic glass popped like popcorn, and it's the single most useful thing you can add to a bag of compost. It holds almost no water, doesn't break down, and doesn't shift your pH bwhat it does is open up permanent air channels. Water drains through and around it, and between waterings those channels fill with air, giving the roots the wet-then-dry rhythm they want. Cheap compost is usually short on it, which is exactly why first grows so often drown. Grab a bag of perlite when you buy your soil and you've covered the most common beginner mistake before it happens.
How much perlite should I add to Ladies soil?
Mix in 20-30% by volume, and lean to the higher end in the final pot where drainage matters most. If your bag of growing media already has some perlite blended through, add more anyway bslightly too much just means the pot dries a touch faster, while slightly too little leaves you one enthusiastic watering away from a swamp.
One rule that catches people: mix it through the medium before you fill the pot, never sprinkle it on top. Drainage happens inside the soil, not on the surface bperlite scattered on top just floats off the next time you water.
Perlite vs vermiculite - which do I need?
They do opposite jobs. Perlite drains and aerates; vermiculite absorbs and holds water. Most Irish growers are fighting too much moisture rather than too little, so perlite is the standard choice and vermiculite usually stays in the cupboard. Vermiculite earns its place in a seed-starting mix bit keeps germinating seeds consistently damp bor in a very hot, dry room, but for a typical indoor grow you can leave it out. If you only buy one, buy perlite.
Which feeding amendments are worth adding?
Once drainage is sorted, a few gentle feeders can help - but go light:
- Worm castings - the gentlest feed there is. Slow-release nitrogen plus beneficial microbes that won't burn the plant. Mix in 10-15% by volume if your soil is light on nutrition. We stock worm castings alongside the soil range.
- Bat guano - high in phosphorus and handy in flower, but concentrated. Overdo it and you get nutrient burn, so beginners are better off with a soil that already doses it correctly than adding it solo.
- Dolomite lime - buffers pH and adds calcium and magnesium. A tablespoon per gallon lifts an acidic mix, though most quality soils already include it.
- Mycorrhizae - beneficial fungi sprinkled on the roots at transplant. They colonise the root zone and help the plant pull in phosphorus and water. Not essential, but a quiet long-game advantage.
Pre-amended organic soils like BioBizz All-Mix already carry a balanced dose of this lot boften the smartest starting point if you'd rather not measure amendments yourself.
How do I avoid over-amending?
Respect what's already in the bag. A good soil is a balanced recipe, and the classic beginner error is piling castings, guano and lime on top of a mix that's already dialled in bthen frying a seedling that only needed a sip of water. The safe approach: add perlite for drainage (you genuinely can't overdo air), keep feeding amendments modest, skip them entirely for seedlings, and treat concentrated inputs like guano with caution. Mix everything thoroughly through the medium before potting. Amendments tune a sound base bthey're not there to build a nutrient bomb.
Sort your soil and amendments in one trip
If you're standing over a bag of compost wondering what to add, the answer is nearly always "more perlite, and not much else." Bring your soil choice to the counter and we'll match the amendments to it. DIG is Ireland's largest grow shop, based in Dublin, with collection available in store and delivery across Ireland.
Want the full breakdown of every amendment and the science behind air-versus-water in the root zone? Our friends at Grow Good Bud have the free in-depth guide.
FAQ
How much perlite should I add to Ladies soil?
About 20 - 30% by volume, and a little more in the final pot for drainage. Mix it through the soil rather than layering it on top, which does nothing.
What's the difference between perlite and vermiculite?
Perlite creates air channels and improves drainage; vermiculite absorbs and retains water. Indoor grows usually want more drainage, so perlite is standard and vermiculite is mostly for seed-starting.
Do I need to add amendments to good soil?
Usually just extra perlite for drainage. A quality soil already balances feeding amendments and pH buffers, so adding more risks over-amending and burning the plant.
Can you have too much perlite?
Hardly bextra perlite just means the pot drains and dries a bit faster, which is easy to manage with watering. Too little is the real risk, so when in doubt, add more.
Where can I buy perlite and amendments in Ireland?
DIG (Dublin Indoor Gardening) stocks perlite, worm castings, pre-amended soils and the rest of the growing-media range, with collection in Dublin and delivery across Ireland.
