Fertilizer
Fertilizer is used to support crop growth and assist in farming. Some fertilizer is used by placing it on tilled soil before placing the respective seeds; other fertilizer can be used after planting a seed, as well as during plant growth.
Fertilizer remains in the soil all season. When the season changes, fertilizer normally disappears. However, if a cross-season crop like Corn is fertilized, the fertilizer will remain in the soil and continue to provide benefits. Fertilizer in the greenhouse, however, will disappear after one season, even with crops that are normally cross-season.
Removing a crop with a Tool like the Pickaxe does not remove the fertilizer. Only one type of fertilizer may be used per soil tile.
Types of Fertilizer
| Image | Name | Description | When to Use | Pierre's | Oasis | Sell Price | Ingredients | # Produced per Craft | Recipe Source |
|---|---|---|---|---|---|---|---|---|---|
 |
Basic Fertilizer | Improves soil quality a little, increasing your chance to grow quality crops. Mix into tilled soil. | Before planting |  100g
|
2g
|
 Sap (2)
|
1 |  Farming Level 1
| |
 |
Quality Fertilizer | Improves soil quality, increasing your chance to grow quality crops. Mix into tilled soil. | Before planting | 150g
|
10g
|
Sap (2) Fish (1)
|
1 | Farming Level 9
| |
 |
Basic Retaining Soil | This soil has a chance of staying watered overnight. Mix into tilled soil. | Before or after planting | 100g
|
4g
|
 Stone (2)
|
1 | Farming Level 4
| |
 |
Quality Retaining Soil | This soil has a good chance of staying watered overnight. Mix into tilled soil. | Before or after planting | 150g
|
200g
|
5g
|
Stone (3) Clay (1)
|
1 | Farming Level 7
|
 |
Speed-Gro | Stimulates leaf production. Guaranteed to increase growth rate by at least 10%. Mix into tilled soil. Does not reduce time between harvests for multi-harvest crops. | Before or after planting | 100g
|
20g
|
 Pine Tar (1) Clam (1)
|
5 | Farming Level 3
| |
 |
Deluxe Speed-Gro | Stimulates leaf production. Guaranteed to increase growth rate by at least 25%. Mix into tilled soil. Does not reduce time between harvests for multi-harvest crops. | Before or after planting | 150g
|
80g
|
40g
|
 Oak Resin (1) Coral (1)
|
5 | Farming Level 8
|
Quality Crop Ratios
Assuming level 10 Farming skill, Basic Fertilizer gives an equal chance of obtaining regular, silver, or gold quality crops (≈33% each).
Quality Fertilizer gives the following ratios (again, assuming Level 10 Farming skill): ≈10% Regular / ≈30% Silver / ≈60% Gold.
Appearance
Once used on tilled soil, each type of fertilizer has a unique appearance, allowing you to see what type of fertilizer has been used on a given tile.
| Name | Unwatered | Watered |
|---|---|---|
| Basic Fertilizer | 
|
|
| Quality Fertilizer | 
|
|
| Basic Retaining Soil | 
|
|
| Quality Retaining Soil | 
|
|
| Speed-Gro | 
|
|
| Deluxe Speed-Gro | 
|
|
Tips
Crafting Fertilizers is always a better option than buying them, and will save you a lot of money throughout the course of the game.
Sap is very easy to come by (from cutting Trees and killing Slime), so remember to craft Basic Fertilizer as soon as you hit Farming Level 1. It is well worth it.
When you reach Fishing Level 3, a good tip is to craft a number of Crab Pots and place them in the small lakes within your farm + a few by the ocean. Use the caught Periwinkles, Snails, Shrimps, Mussels and Oysters (classified as Fish) to combine with Sap to make Quality Fertilizer. Easy and cheap.
Speed-Gro and Deluxe Speed-Gro variants are also cheaper to craft than to buy.
For each Pine Tar/Clam combo, you actually get five Speed-Gro packs (1 Pine Tar + 1 Clam = 5 Speed-Gro), which saves both money and resources. Same goes for Deluxe Speed-Gro (1 Oak Resin + 1 Coral = 5 Deluxe Speed-Gro), so get those Tappers up and running.
| Image | Name | Cost Item | Price | Saving |
|---|---|---|---|---|
|
|
Speed-Gro x 5 |
Pierre's |
| |
|
|
Deluxe Speed-Gro x 5 |
Pierre's Oasis |
|