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Biotabs Startrex 1.5kg
Biotabs Startrex 1.5 kg is a certified 100% organic soil conditioner (NPK 3-1-2) that restores biological activity in sterilised potting mixes and coco coir substrates. The concentrated powder delivers probiotic bacteria, fulvic acid and silicon — three components that work synergistically to improve substrate structure, accelerate root establishment and enhance uptake of organic fertilisers. Application rate is 25 grams per 5 litres of substrate, mixed thoroughly before potting. The 1.5 kg format treats approximately 300 litres of growing media, positioning it as the standard size for mid-scale indoor and outdoor operations. Explore how biologically active substrate transforms organic cultivation performance.
Biotabs Startrex 1.5 kg — organic soil conditioner with probiotic bacteria, fulvic acid and silicon
The limiting factor in most organic growing systems is not the fertiliser — it is the biological activity of the substrate. Commercial potting mixes and coco coir are sterilised during manufacturing, eliminating pathogens but simultaneously destroying the beneficial microorganisms responsible for converting organic matter into plant-available nutrients. Biotabs Startrex directly addresses this bottleneck by delivering a concentrated payload of probiotic bacteria, fulvic acid and silicon into the growing media in a single mixing step. The 1.5 kg format treats up to 300 litres of substrate, making it the go-to size for mid-scale operations. Available from Biotabs.
Active components and their functional roles
Startrex's effectiveness stems from the synergy between three distinct active components:
- Probiotic bacteria — a broad-spectrum consortium of beneficial soil microorganisms that colonise the substrate within hours of hydration. These bacteria decompose organic matter into plant-available nutrients, improve soil aggregation and suppress pathogenic organisms through competitive exclusion.
- Fulvic acid — a low-molecular-weight organic acid that functions as a natural chelating agent and nutrient transporter. Fulvic acid increases cell membrane permeability, enabling more efficient mineral uptake at the root level and facilitating nutrient delivery directly into plant cells.
- Silicon (Si) — strengthens cell walls, increasing stem rigidity and improving plant tolerance to heat stress, drought and pathogen pressure. Silicon also modulates stomatal regulation, helping plants manage transpiration more effectively under variable environmental conditions.
Application method
Mix 25 g of Startrex per 5 litres of potting soil or coco coir. Ensure thorough, uniform distribution throughout the substrate before potting. The bacteria in Startrex are preserved in a dehydrated dormant state and activate upon contact with water. Substrate colonisation begins within hours of the first irrigation, establishing a functional microbial ecosystem from day one of cultivation.
For the complete Biotabs growing method, combine Startrex with Mycotrex mycorrhizal inoculant in the planting hole and BioTabs fertiliser tablets for slow-release nutrition. These three products form the foundation of the biological growing system.
1.5 kg format: capacity and use case
At the standard application rate, 1.5 kg yields 60 individual doses of 25 grams — sufficient to treat 300 litres of growing media. This covers a full cycle of 15 to 30 plants in 10-20 litre containers, including substrate revitalisation between harvests. Growers operating at higher volumes should consider the 5 kg bulk format for a lower per-kilogram cost.
Biotabs Startrex is certified 100% organic (NPK 3-1-2). Order from Plant&Flower for fast shipping across Belgium.
How much Biotabs Startrex do I need per pot?
Use 25 grams (2 tablespoons) of Startrex per 5 litres of potting soil or coco coir. For a 10-litre container, use 50 grams. Mix the powder uniformly through the substrate before potting to ensure even distribution of the probiotic bacteria.
Can Startrex be used to revitalise reused substrate?
Startrex is highly effective for substrate revitalisation. After harvest, remove the top 5 cm of spent media, replace with fresh substrate and mix in 25 grams of Startrex per 5 litres. The probiotic bacteria will reinoculate the existing substrate and restore microbial activity to optimal levels.
What is the difference between Biotabs Startrex and Bactrex?
Startrex is a soil conditioner mixed into the substrate before potting, containing probiotic bacteria, fulvic acid and silicon (NPK 3-1-2). Bactrex is a root zone protectant dissolved in irrigation water, specifically containing Trichoderma fungi and Bacillus bacteria for pathogen suppression. The two products serve complementary functions and are designed to be used together.
How many litres of substrate does 1.5 kg of Startrex treat?
At the recommended rate of 25 grams per 5 litres, a 1.5 kg pack treats approximately 300 litres of potting soil or coco coir. This provides 60 individual applications, enough for a complete cultivation cycle with 15 to 30 plants in standard containers.
