Ultracompost is the most potent version of compost and is used in conjunction with the Farming skill. It is created by filling a compost bin with 15 buckets of dragon manure or 750 dinosaur 'propellant' and then collecting it with empty buckets after the composting process is done, giving 15 Ultracompost. This amount can be increased if the "Bully for You" totem perk is active at a player-owned farm's large pen.
A plant that has been treated with ultracompost has a 7% chance of dying, half that of supercompost, which has a 14% chance. Despite what its examine text may suggest, ultracompost does not make crops grow faster.
For herb, hops, and allotment patches, using ultracompost will increase the number of harvest lives by 3 (from a starting number of three lives). Every harvest action will roll a chance out of 255 on the specific patch's "Chance to Save" table, taking one of the harvest lives from the patch if it does not hit, with the patch becoming empty when it runs out of lives. This chance is dependent on Farming level and other boosts (magic secateurs, greenfingers aura, juju farming potion, master farmer outfit, etc). Compared to supercompost, which increases harvest lives by two, using ultracompost will increase yield by 20%.
For herb, hops, and allotment patches, taking into account the odds of dying, as well as the number of harvest lives given, the expected yield of a crop treated with ultracompost is about 30% better than one treated with supercompost. One should use ultracompost only if these 30% cover the difference in price between supercompost and ultracompost. It should be noted that the cost of the seeds is irrelevant for choosing between composts, only the price of the products needs to be considered.
If the "Dragon Ultra Combo" totem perk is active at a player-owned farm's large pen, the player has a 1/1,000 (tier 1) or 1/750 (tier 2) chance to receive an ancient effigy while checking a farming patch that has been treated with ultracompost.
Ultracompost can be applied automatically by a tool leprechaun for 2,500 coins per bucket, provided that the payment has been made before clearing the patch, and that the leprechaun has some stored.
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