Hormex Rooting Powder comes in four strengths: #1, #3, #8 and #16. Each number tells you how much IBA (the rooting hormone) is in the powder, from 0.10% to 1.60%. Easy-to-root cuttings need a low strength, and tough woody cuttings need a high one. Using a stronger powder than your plant needs does not root it faster and can damage the cutting, so the right strength matters more than the strongest one.
Hormex rooting powder strength chart
| Strength | IBA | Best for | Plant examples |
|---|---|---|---|
| #1 | 0.10% | Tender softwood cuttings: easy-to-root houseplants, herbs and soft new growth | African violet, hydrangea, pothos, coleus, basil, geranium |
| #3 | 0.30% | Firmer semi-softwood cuttings: many flowering and garden plants | Rose, gardenia, camellia, lavender, fig, rhododendron |
| #8 | 0.80% | Semi-hardwood cuttings: woody shrubs, vines and trees | Azalea, blueberry, hibiscus (semi-hardwood; use #3 for soft green cuttings), fiddle leaf fig, grape, lilac, maple, oak |
| #16 | 1.60% | Difficult-to-root hardwood cuttings: tough woody plants, evergreens and trees | Hollywood juniper, English yew, English holly, sugar maple, eastern red cedar |
Don't see your plant? Search the Hormex plant guide for the recommended strength for hundreds of plants.
Growing consumables? Hormex Rooting Powders are free of dyes, preservatives and alcohol, so they’re a great fit for cloning consumable plants, from food crops to medicinal plants. Always follow the label directions.
What the numbers mean
Each Hormex strength is named after its IBA concentration. Divide the number by 10 to get the percentage of IBA: #1 is 0.10%, #3 is 0.30%, #8 is 0.80% and #16 is 1.60%.
IBA (indole-3-butyric acid) is an auxin, a plant hormone that encourages a cutting to form new roots. The faster a cutting roots, the better its chance of becoming a healthy new plant. Hard-to-root plants need more IBA to get started, while easy-to-root plants need very little.
Why stronger isn’t better
Think of it like caffeine. A cup of coffee helps you get going, but a whole pot leaves you too jittery to get anything done. Rooting hormone works the same way: tough hardwood cuttings like juniper and yew need the concentration of #16, but the same strength on a soft houseplant cutting can burn the stem and stall rooting. Matching the strength to the cutting gives each plant the amount of IBA it can use.
How to choose your strength
- #1Soft, green, bendy stems (houseplants, herbs, new spring growth)
- #3Firmer green stems that are starting to mature (many flowering and garden plants)
- #8Partly woody stems from this season’s growth (shrubs, vines and fruit trees, late summer into fall)
- #16Fully woody, dormant stems (evergreens and hard-to-root trees, late fall into winter)
When in doubt, look up your plant in the plant guide. If it lists two strengths, use the lower one for softer cuttings and the higher one for woodier stems. For example, tropical hibiscus uses #3 for soft, green cuttings and #8 for firm, brown ones. Try our quick bend test to choose.
How to use Hormex Rooting Powder
- Find the node. Use clean shears to cut just below a node, then remove the lower leaves.
- Moisten, dip and tap. Lightly moisten the base with clean water, shake off the excess, dip it in the powder and tap off the excess.
- Plant the node. Place the cutting in rooting cubes, rockwool, coco coir, peat moss or soil without rubbing off the powder.
- Keep it lightly moist. Keep the medium lightly moist, not waterlogged.
Pour a small amount of powder into a separate dish for each batch, and never return unused powder to the container. See How to Use Hormex Products for full directions.
Sizes for home gardeners and growers
Every strength comes in a 3/4 oz bottle, a 1 lb container and a 6 lb box. Commercial and agricultural growers can contact our team about volume pricing.
#1 Shop Rooting Powder #1#3 Shop Rooting Powder #3#8 Shop Rooting Powder #8#16 Shop Rooting Powder #16
Frequently asked questions
Which Hormex rooting powder is the strongest?
Hormex Rooting Powder #16 is the strongest at 1.60% IBA. It is made for difficult-to-root hardwood cuttings such as Hollywood juniper and English yew. Stronger is not better for easy plants, so match the strength to your cutting.
What do the numbers on Hormex Rooting Powder mean?
The number shows the IBA concentration. Divide it by 10 to get the percentage: #1 is 0.10% IBA, #3 is 0.30%, #8 is 0.80% and #16 is 1.60%.
What if my plant lists two strengths?
Use the lower strength for softer, younger cuttings and the higher strength for older, woodier stems from the same plant.
Can I use the strongest powder on every cutting?
No. Easy-to-root cuttings like houseplants and herbs do best with a lower strength such as #1. Too much IBA can damage tender stems and slow rooting instead of speeding it up.
Can I use Hormex Rooting Powder on consumable plants?
Yes. Hormex Rooting Powders are free of dyes, preservatives and alcohol, which makes them a great fit for cloning consumable plants, from food crops to medicinal plants. Always follow the label directions.
