Osmocote Smart-Release Plant Food Plus (15-9-12) Review (2026)
By The DIYPicks Team · Updated July 2026
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- All purpose
- Containers
- Flowers
- Vegetables
The easiest all-purpose choice for containers and mixed beds: mix the prills in once and they meter out nutrients for the whole season with almost no burn risk.
Pros
- One application feeds up to 6 months, so far fewer trips with a bag
- Temperature/moisture-triggered coating releases gradually with very low burn risk
- 11 essential nutrients; works indoors and out on nearly any plant
Cons
- Costs more per pound than uncoated granular fertilizers
- Fully synthetic; contributes no organic matter to the soil
- Release slows in cold soil, so early-season plants may need a supplemental feed
Specifications
| NPK | 15-9-12 |
|---|---|
| Type | Resin-coated granular prills |
| Release | Slow, feeds up to 6 months |
| Coverage | 8 lb covers ~600 sq ft (about 1 lb per 20 sq ft) |
| Best for | Set-and-forget feeding of containers & beds |