Sprinklers and Fertilizers
Complete guide to all sprinkler tiers and fertilizer types in Starsand Island. Includes sprinkler costs, coverage areas, crafting materials, Fertilizer Box progression from I to V, and exact growth-time reductions for each Ripening and Yield fertilizer tier.
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Sprinklers and Fertilizers overview
Sprinklers and fertilizers are the two most important upgrades for your farm on Starsand Island. Sprinklers automate daily watering so you can spend time on other activities, while fertilizers boost crop growth speed and harvest yields. Both are unlocked through the Farmer profession at the Happiness Seed Shop run by Graminova. Investing in sprinkler and fertilizer upgrades early is one of the most efficient ways to scale your farm income.
Sprinkler tiers
There are five sprinkler tiers, each watering a larger area around itself. Sprinklers are placed between crop tiles and automatically water surrounding crops every morning. Higher-tier sprinklers cover more tiles and reduce the number of sprinklers you need for a given plot.
Sprinkler | Farmer Rank | Cost | Coverage |
|---|---|---|---|
Sprinkler (Base) | Apprentice | 1,500 Gold | 4 adjacent tiles (cross pattern) |
Sprinkler I | Junior | 3,000 Gold | 8 surrounding tiles (3x3 area) |
Sprinkler II | Intermediate | 8,000 Gold | 12 tiles (extended 3x3 area) |
Pressurized Sprinkler | Senior | 15,000 Gold | 24 tiles (5x5 area) |
Sprinkler III | Expert | 25,000 Gold | 48 tiles (7x7 area) |
Sprinkler blueprints are purchased from Graminova at the Happiness Seed Shop. After buying the blueprint, you craft the sprinkler at your workstation using crafting materials (typically iron ingots, copper wire, and pipes that scale with tier).
Sprinkler placement tips
Place sprinklers before planting to avoid accidentally destroying crops when placing them later
Each sprinkler operates independently. Overlapping coverage areas do not cause problems
The Sprinkler I at Junior Farmer tier is the most important early unlock. Buy it immediately when it becomes available
For maximum efficiency, arrange crops in a grid pattern centered on sprinklers. A single Sprinkler III can cover a full 7x7 plot
Sprinklers work year-round including inside the Greenhouse (Expert Farmer)
Fertilizer types
Fertilizers are applied directly to crop tiles to modify growth speed, harvest yield, or special properties. There are four fertilizer categories, each with multiple tiers. Apply fertilizer before or during the growth cycle. The effect persists until the crop is harvested.
Fertilizer | Effect | Exact Bonus |
|---|---|---|
Ripening Fertilizer I | Shortens crop growth time | Reduces growth by 8 hours |
Ripening Fertilizer II | Shortens crop growth time | Reduces growth by 13 hours |
Ripening Fertilizer III | Shortens crop growth time | Reduces growth by 25 hours |
Yield Fertilizer I | Increases harvest quantity | +50% more items per harvest |
Yield Fertilizer II | Increases harvest quantity | +150% more items per harvest |
Gmax Fertilizer III | Chance of mutation | 15% chance to produce a mutated crop variant |
Nutrient Soil IV | Boosts pollination | 15% increased pollination rate for cross-breeding |
Ripening Fertilizers are the most universally useful. Ripening III cuts nearly a full day off growth, which means you can fit in extra harvest cycles per season. Yield Fertilizers are best for high-value crops like Star Mango and Stardew Fern where each extra item matters. Gmax Fertilizer III is primarily used to obtain rare Everlasting crop variants. Nutrient Soil IV is essential for cross-breeding flowers and hydrangeas.
How to apply fertilizers
Select the fertilizer from your inventory
Walk to the crop tile you want to fertilize
Use the item on the tile (same interaction button as planting)
A small icon appears on the tile indicating the active fertilizer type
Only one fertilizer type can be active on a tile at a time. Applying a new type replaces the previous one.
Fertilizer Box progression
The Fertilizer Box is a crafting station that produces fertilizer from raw materials (crop waste, animal waste, compost). Higher-tier boxes produce better fertilizer and work faster. Blueprints unlock through Farmer profession rank:
Station | Farmer Rank | Produces |
|---|---|---|
Fertilizer Box I | Apprentice | Ripening Fertilizer I, Yield Fertilizer I |
Fertilizer Box II | Junior | Ripening Fertilizer II |
Fertilizer Box III | Intermediate | Ripening Fertilizer III, Yield Fertilizer II |
Fertilizer Box IV | Senior | Gmax Fertilizer III |
Fertilizer Box V | Expert | Nutrient Soil IV, all lower tiers |
You can also buy fertilizers directly from the Happiness Seed Shop, but crafting them at home is cheaper long-term if you have a steady supply of compost material.
Seasonal farming strategy
Fertilizer and sprinkler strategy changes by season. In Spring, focus on Ripening Fertilizer to get early harvests of fast-growing crops. In Summer, use Yield Fertilizers on high-value crops like Watermelon. In Autumn, prioritize Gmax Fertilizer to obtain Everlasting variants before Winter arrives. During Winter, the Greenhouse (Expert Farmer) allows year-round growing. Equip it with Sprinkler III and Yield Fertilizer II for maximum output.
Tips
Priority unlock order: Sprinkler I (Junior) > Fertilizer Box I (Apprentice) > Sprinkler II (Intermediate) > Fertilizer Box III (Intermediate)
Ripening Fertilizer III + Sprinkler III is the endgame combo for maximum farming efficiency
Nutrient Soil IV is the only fertilizer that affects flower cross-breeding success rates
Yield Fertilizer II (+150%) stacks multiplicatively with crop quality bonuses, making it extremely profitable on Gold-quality crops
Crafting fertilizer at home with the Fertilizer Box saves significant money compared to buying from the shop, especially at higher tiers
Always keep at least 20 Ripening Fertilizer on hand for re-planting cycles after each harvest