Visit the preferences page while blackcurrant seed in and turn on the gadget. They can be used to craft Green Thread.
They also can be used to craft Leafy Jungle Wall and Jungle Vine Wall. Charging through the entire surface jungle cutting down every single plant may only yield a few seeds. It is worth remembering though that Jungle Grass will spread to adjacent open Mud Blocks just as with any other Grass, if slowly. If you’ve found the Flower Boots in a Jungle Shrine chest, you can produce plants as quickly as you can cut them down.
Running around on existing Jungle grass while cutting the flowers produces Jungle Grass Seeds very quickly despite the low drop rate. It is possible to “convert” Mushroom Grass Seeds into Jungle Grass Seeds if the planted mushroom grass is sprayed with Green Solution. This will turn the mushroom grass into Jungle grass. It is possible to find the rare items such as Nature’s Gifts in a player-made Underground Jungle.
The most efficient setup for creating an Underground Jungle “farm” for harvesting Jungle Spores, Jungle Seeds, and Nature’s Gifts, is to place a floor of jungle grass, and a ceiling 3 blocks in height. On the next layer up, do the same, but this time also add a middle layer so you have 3 lines with 1 space between each, and repeat. This method is sometimes questioned due to the vines that can hang down and prevent some items spawning. However, in Underground Jungle biomes, grass and roses seem to grow faster than vines, so this should result in better yields in a smaller space than a simple 3 block high tunnel farm. Natural Underground Jungles begin below -60 feet in a small world, -90 feet in a medium world, and -120 feet in a large world. An artificial jungle will become inhabited with the respective enemies. Jungle Grass grows at a rate comparable to Mushroom Grass, which is much slower than ordinary Grass.