Calculate the perfect ratio of coco coir, vermiculite, gypsum, and grain spawn for optimal substrate composition. Get exact measurements for your monotub or growing container in seconds.
CVG stands for Coco Coir, Vermiculite, and Gypsum - the three primary ingredients in one of the most popular bulk substrates for mushroom cultivation. This substrate mix is particularly effective for growing oyster mushrooms, lion's mane, and many other gourmet varieties.
The 2:2:1 ratio (coir:vermiculite:gypsum) has been proven through years of cultivation experience to provide:
Your spawn rate determines how quickly your substrate will colonize:
Slower colonization (14-21 days), higher contamination risk, lower cost
Optimal balance of speed (7-14 days), contamination resistance, and cost-effectiveness
Fastest colonization (5-10 days), lowest contamination risk, highest cost
While the 2:2:1 ratio is standard, you can adjust based on your specific needs:
You can create a coir-only substrate or substitute with peat moss. Vermiculite adds structure and drainage, but many growers successfully use 100% coir. You may need to adjust water content slightly.
Yes, both work well. Agricultural gypsum (calcium sulfate) is preferred for purity, but garden gypsum is acceptable. Avoid gypsum with additives or colored varieties.
Coco coir typically requires 5-6 times its dry weight in water. The calculator provides base measurements, but always perform the squeeze test: a properly hydrated substrate releases 2-3 drops when firmly squeezed.
While not absolutely required, pasteurization significantly reduces contamination risk. Heat your mixed substrate to 160-170°F for 90 minutes. Many successful growers skip this step with clean technique, but beginners should pasteurize.
Slow colonization can result from: low spawn rate (<20%), low temperature (<70°F), poor spawn quality, over-hydrated substrate, or contamination. Check temperature first and ensure your spawn rate is at least 20-25%.
Yes! A healthy substrate typically produces 2-4 flushes. Between flushes, remove old mushroom stumps, soak the substrate for 12-24 hours (dunking), and return to fruiting conditions. Quality decreases with each flush.
Pasteurized substrate should be used within 24-48 hours. After that, beneficial microbes begin to multiply and contamination risk increases. Always spawn substrate when it's at room temperature and freshly prepared.