Soil Amendments
Perlite and vermiculite to open up a mix or help it hold moisture, plus Biobizz Worm Humus and Pre-Mix and Ecothrive Charge to feed the soil itself. Sold in the Bristol shop and by post across the UK.
In StockBiobizz
£22.46
In StockEcothrive
£5.36
In StockBiobizz
£11.66
In StockPLANT!T
£10.76
In StockPLANT!T
£13.01
About Soil Amendments
Perlite and vermiculite: what's the difference?
Perlite is expanded volcanic glass: light, white and porous. Mixed into soil or coco at 10 to 30 per cent it opens the mix so water drains and air reaches the roots. It is the usual fix for a heavy or waterlogged compost.
Vermiculite is expanded mica. It holds water and nutrients and releases them slowly, which makes it the better choice for seed sowing, cuttings and any mix that dries out too fast. Many growers use both: perlite for air, vermiculite for moisture. Both are sterile, neutral and never rot.
Feeding the soil
Biobizz Worm Humus is pure worm cast, rich in humic compounds and microbial life; add it to a mix at up to a fifth by volume. Biobizz Pre-Mix is a dry organic fertiliser blend worked into soil before planting so the mix feeds itself for weeks. Ecothrive Charge is insect frass, a gentle organic feed that also triggers the plant's own defences against pests.
Growers' Guides
- Mycorrhizae, Trichoderma and Beneficial Bacteria for PlantsMycorrhizae, Trichoderma and beneficial bacteria: what they do, when to add them in soil, coco or hydro, and the microbial products we sell compared.
- Which Potting Soil? Biobizz, Canna Terra, Plagron and Gold LabelBiobizz All Mix vs Light Mix, Canna Terra Professional vs Plus, Plagron Batmix and Gold Label compared: how much food each soil carries and when to feed.
- Soil Amendments and Living Soil: Worm Castings, Frass, Pre-MixSoil amendments for living soil: what worm castings, insect frass, Biobizz Pre-Mix and mycorrhizae do, which soils already have them and when to add each.
- Sowing Seeds Indoors: How to Germinate, Prick Out and Harden OffHow to germinate seeds indoors, choose a seed propagator, prick out and transplant seedlings, what to feed them and how to harden them off.
- Perlite vs Vermiculite: What They Are and When to Use EachWhat perlite and vermiculite are, how they differ, which to use for seeds, cuttings, soil and coco, and the soils and mixes we sell with perlite in them.
- Biobizz Feed Chart 2026: All·Mix and Light·Mix SchedulesThe Biobizz feed chart week by week for Light·Mix, Coco·Mix and All·Mix: Bio·Grow, Bio·Bloom, Top·Max, Root·Juice and the boosters in ml per litre.