Spawn+Production

Spawn is a highly concentrated mycelium culture, used to inoculate bulk substrate for mushroom caps production, or to produce more spawn. Spawn is most frequently based on grain or sawdust. It is made initially from agar culture, and then from previous grain culture - called grain to grain transfer G2G, for a maximum of four generations. media type="custom" key="24754762" align="right"


 * Materials**
 * 1) **Grain or sawdust** : see grain medium or sawdust medium pages.
 * 2) **Agar or Grain spawn** : For transfer from agar culture, RR uses a third of 10 cm plate to inoculate a quart jar (250gr of dry grain) [3]. For grain spawn quantity, Stamets is unclear whether it is 1.5-3.5% or 3-7% of dry spawn/dry substrate. RR advise to use 10% of final weight (1 jar to make 10 new jars) [2]. Commercial grain spawn sold for bulk substrate inoculation may not be appropriate, as mycelium may already expanded too much likely to produce senescent spawn.
 * 3) **Culture containers (jars or bags)** : see culture jars or culture bags pages
 * 4) **Spoon**


 * Procedure**
 * 1) Grain substrate must be prepared and sterilized, as explained in detail in Grain Medium page and Heat Sterilization pages, grain kernels must be soaked and sterilized. The spoon must be sterilized with the grains.
 * 2) Clean your sterile workspace (e.g. GloveBox or Laminar Flow Hood). Place inoculating spawn, new sterilized grain or sawdust containers and the spoon in your workspace. Make your workspace sterilization procedure (e.g. mist with 70° alcohol, let rest and rub the surfaces). media type="custom" key="23658968" align="right"
 * 3) Open your spawn, break enough for a jar, with the spoon (you can weight your spoon and jars before working in sterile conditions, or have a scale in your workspace sterilized.with alcohol.
 * 4) Open a grain container and place the pieces of spawn inside, on the top of the grain. Close back the container
 * 5) Redo steps 3 and 4, until no grain container or spawn is left
 * 6) Store in an incubator or a clean place with best temperature for your species


 * Expected Results**
 * Within few days you should see the white mycelium colonizing the container
 * A week is usually enough time to see if contamination - such as trichoderma, develop, in this case best is to discard the contaminated container, but there is ways to fight contamination.
 * Few weeks are enough for full expansion, but expansion time greatly depends on mushroom species and incubation conditions - especially temperature. After that moment, the spawn should be used or can be stored (up to 1 year), but in this case possibly loosing vigor.

**Stamets about Inoculation Rate**: "The preferred rate of inoculation depends upon many factors, not the least of which is cost. If a cultivator buys spawn from a commercial laboratory, the recommended rate is often between 3-7% of substrate mass. What this means is that for every 1000 lbs. of substrate (dry weight), 30-70 lbs. of spawn (wet weight) is suggested. Since grain spawn is usually around 50% absolute moisture, this rate of inoculation would be equivalent to 1. 5-3. 5% of dry spawn/dry substrate." [1]


 * References**
 * 1) p128, Growing Gourmet and Medicinal Mushroom- Paul Stamets
 * 2) [|Grain to grain transfer, "Let's grow mushrooms" DVD, by RR]
 * 3) Sterile inoculation procedure (agar to grain), "Let's grow mushrooms" DVD, by RR