Glowing Mushroom Spores are small cyan blue types of Seeds that can be used to grow Glowing Mushrooms.
Glowing Mushroom Spores can be received as a random extra harvest whenever you collect blocks of Glowing Mushrooms on the Stalactite layer (requires an Obsidian Mining Cell or better Power Cell to be equipped). The chances to receive additional Mushroom Spores is very random, but a rather rare occurrence when mining wild Mushrooms.
Glowing Mushroom Spores can be planted in order to grow Glowing Mushrooms, mainly for decoration purposes. They are cyan blue just like Glowing Mushrooms themselves and glow a little in the dark, but they do not spend light.
Special looking Glowing Mushrooms can be grown from Glowing Mushroom Spores. They are not embedded in Siltstone, but flat. These player-grown Glowing Mushrooms also glow brighter and in different colors than "naturally" occurring Glowing Mushrooms.
You can even safely remove the block that you grew Glowing Mushrooms on and replace the block.
When harvesting player-grown Glowing Mushrooms, 6-10 Glowing Mushrooms will be received and rather often 1 additional batch of Glowing Mushroom Spores on top of that since update R60 on February 7th 2019.
Other than that, Glowing Mushroom Spores can also be put on display in display containers or placed directly into the world as a decoration.
How to obtain
1 Glowing Mushroom can be processed into 1 unit of Glowing Mushroom Spores.
This does not require any crafting recipes to be unlocked.
Simply carry Glowing Mushrooms with you in your inventory and activate a Processor in the game world with right-click or "f" (as the default key) while pointing your mouse cursor at the Processor.
However, Glowing Mushroom Spores can be captured with a Capture Block. Such, you can buy more of them as part of building kits for Blueprints, and quite cheap as well - either for Blueprints that you have captured yourself, or Blueprints that were made by other players and that you have subscribed to in the Steam Creativerse workshop, or Blueprints that you have customized with Mushroom Spores.
Building kits can be paid with ingame Coins that can be bought with real money via Steam Wallet in the Store. To buy a building kit, either select the according Blueprint or activate a cornerstone that has been placed into the game world (and has optionally been customized). Check the content of the block kit first by clicking on the description "Built with xxx Blocks" before you'll click on the green price tag button below "Get kit and build now".
How to use
Glowing Mushroom Spores can be planted on top of blocks of Dirt, Grass, Mud or tilled land (created from the aforementioned natural blocks with a Plow) with moisture adjacent. Other natural ground blocks then these 3 known types do not seem to be suited as a substrate for Mushrooms.
In order to plant them, simply place one unit of Glowing Mushroom Spores by putting (a stack of) them into your quickbar, select the according quickslot and use right click while pointing at the spot of ground where you want to the Glowing Mushrooms to grow.
If the Glowing Mushroom Spores are planted in a suitable environment with a unit of Water, Mineral Water or Bog Water (not too many units of Bog Water nearby though!) adjacent to the block they are placed on, they will grow into 1 unit/batch of Glowing Mushrooms each after 10 minutes real time. Otherwise, the Spores will stay fallow.
If Glowing Mushroom Spores stay fallow, you can simply pick them up again and plant them somewhere else. No Power Cell has to be equipped for this. As usual, you cannot pick up anything in game worlds, player claims or Adventures where you have the permission rank of a "visitor". You also cannot place anything under such circumstances though.
Very cold biomes (like Taigas or snow-covered Tundras), very high altitudes (like the top of snow-covered Mountains over 150 blocks) and very hot biomes (like the Lava layer) are unsuitable to grow Mushrooms.
Like Crops and Queen Bees, Mushrooms do not need any light in order to grow from Spores.
Glowing Mushrooms can be planted in caves underground (only on the listed suitable blocks of substrate) if you wish to illuminate the area without preventing Creatures and randomly appearing Treasure Chests from spawning. Mushrooms can also be planted under water or emerged in other liquids.
If fertilized with Pigsy Droppings, Glowing Mushrooms will immediately grow from the Spores. Fallow Glowing Mushroom Spores cannot be fertilized though. Different to Crops, Mushrooms do not have several growth stages, but only one stage: "grown".
Upon harvesting (which does not require any Power Cell to be equipped), 6-10 units/batches of Glowing Mushrooms can be obtained from the spot where 1 batch of Glowing Mushroom Spores was planted, no matter what type of soil, moisture or if fertilizer was used. Also, 1 batch of Glowing Mushroom Spores can randomly be received on top of that rather often.
Glowing Mushrooms can be multiplied by planting them, like Crops (Wheat, Turnips, Horned Melons and Crisphead Lettuce), but different to Red Mushrooms, Brown Mushrooms - these Mushrooms can merely be planted for decoration purposes.
Glowing Mushroom Spores can be placed into the slots of display containers for decoration, like in/on Placemats, Stone Wall Shelves, Galactic Grav-Chambers, Wood Planters, Flower Pots, Hidden Temple Altars, Frozen Containers, Snow Buried Containers, Holiday Decorative Trees, Holiday Mantles or the like.
However, the Spores are very tiny and will even be invisible in some display containers. Different to Seeds of Crops, Glowing Mushroom Spores do not sparkle when on display; and the Spores do not illuminate their surrounding in any way.
Glowing Mushroom Spores can also be placed into the game world as a decoration (since they faintly glow) on blocks where they would usually grow into Mushrooms, but with no moisture nearby or in unsuitable biomes, so that they will stay fallow.
Until February 7th 2019, only 1 batch of Glowing Mushrooms could be harvested after planting 1 batch of Glowing Mushroom Spores, and only very rarely 1 additional batch of Spores. This was changed with update R60.