BioTabs PK Booster Compost Tea

A brewed, living organic feed for phosphorus- and potassium-hungry flowers

PK Booster Compost Tea is a concentrated dry blend of composted grape marc (wine production waste), composted manure, bat guano and kelp meal, carrying phosphorus-releasing and potassium-mobilising bacteria. Rather than mixing and pouring like a standard liquid feed, it's brewed: stir roughly 15g — about a tablespoon — into a litre of room-temperature, dechlorinated water along with 5ml of Orgatrex as bacterial food, then aerate with a pump for 24-36 hours to build up the microbial population before using it on the growing medium within about four hours of the aeration stopping.

BioTabs list it among their organic flowering boosters, and it's aimed at soil and outdoor or indoor pot growers who want a genuinely biological route to bloom-stage P and K rather than a bottled mineral salt. Growers running a living-soil or no-till approach can also stir in a teaspoon of Mycotrex mycorrhizal inoculant half an hour before the brew finishes, and roughly a pint of finished tea is used per plant, poured onto the medium while keeping the tea moving.

Because it's a live product it needs a little more attention than a shelf-stable bottle — brewed tea only holds its potency for a few hours and should be made up in small batches with an aeration pump rather than stockpiled, and the compost itself may show natural mould in storage, which BioTabs note doesn't affect quality.

• Live, biologically brewed feed — aerated for 24-36 hours to build beneficial microbial populations before use.
• Phosphorus and potassium from real biology — bat guano, kelp and composted grape marc carry P-releasing and K-mobilising bacteria.
• Pairs with the wider BioTabs range — brew with Orgatrex as bacterial food, or add Mycotrex before finishing.
• Suits living soil and organic set-ups — for indoor and outdoor pot or in-ground growing.
• Concentrated dry blend — a little goes a long way once brewed into tea.