When and How to Apply Winter Fertilizer to Roses

The application of winter fertilizer to roses has always been a topic of debate. Some believe that since roses are dormant during winter, they don't require much fertilizer, and applying it would be a waste. However, this isn't entirely true. Applying organic fertilizer in winter can promote the swelling of rose buds and help maintain soil temperature. Winter is also an optimal time for applying raw fertilizer. If you use well-fermented organic fertilizer, you can apply it once as the winter begins. In northern regions, it's best to apply it before the ground freezes to help insulate the soil.

For raw fertilizer, it should be applied when the temperature is below 5 degrees Celsius, close to freezing. Typically, raw fertilizer is buried in January. The low temperature will consume the heat generated during the fermentation process, reducing the risk of fertilizer burn.

What Kind of Fertilizer Should You Choose for Roses in Winter?

There are many sources of organic fertilizer, such as kitchen waste compost, chicken manure, sheep manure, worm castings, soybean meal, rapeseed cake, fish intestines, and bone meal. How do you choose the right one for your roses?

Generally, organic fertilizers derived from plant residues are higher in nitrogen, while those from animals are richer in phosphorus and potassium. Since roses bloom frequently and have a long flowering period, they consume a lot of phosphorus and potassium. Therefore, it's best to choose organic fertilizers that are high in phosphorus and potassium or have a balanced ratio of nitrogen, phosphorus, and potassium.

Fish intestine fertilizer is a good choice, but it should be used raw. In warmer regions, it may not be safe, and the risk of attracting pests increases. To prevent this, you can use fish intestines with proper pest control measures.

Chicken manure, sheep manure, and worm castings are also excellent choices. These fertilizers have a balanced mix of nutrients, but they may not provide enough phosphorus and potassium for roses. To address this, you can mix them with bone meal to increase the phosphorus and potassium content.

In addition to bone meal, you can also use calcium-magnesium phosphate or superphosphate mixed with sheep or chicken manure to enhance the phosphorus and potassium content, leading to more abundant blooms and vibrant colors.

How to Apply the Fertilizer?

If you're using well-fermented sheep or chicken manure, you can simply loosen the soil and sprinkle the fertilizer on the surface, then gently mix it with the topsoil (suitable for both potted and ground-planted roses).

For ground-planted roses, you can use the shallow burial method. Dig a shallow trench about 10 centimeters away from the roots and bury the fertilizer around the root system. For potted roses, you can bury the fertilizer near the edge of the pot.

For ground-planted roses, raw fertilizer can be used when the temperature is below 5 degrees Celsius. It should be buried at a moderate depth, covering the fertilizer completely. The fertilizer should be buried about 15-20 centimeters away from the root system, with a trench on each side. The amount of fertilizer isn't strictly regulated; just ensure it doesn't touch the roots and is fully covered. More fertilizer will lead to more vigorous growth in the coming year.

For potted roses, it's not recommended to use raw fertilizer due to the uncertainty of potential fertilizer burn. For safety, it's better to use well-fermented sheep or chicken manure.