What is base fertilizer, and is it really necessary to use it?

Here I want to discuss a question that some flower growers often raise: should base fertilizer be added when small rose seedlings are first potted? In my personal understanding, I think that even for small seedlings, base fertilizer can be added, because base fertilizer is usually placed at the bottom of the pot, while small seedlings have short and few roots, so the fertilizer does not actually come into direct contact with the roots.

After the roots have grown for a period of time, when the roots can reach the base fertilizer at the bottom, this first shows that the plant has settled into the pot, and second shows that the plant has grown larger and it is time when it can absorb more nutrients. What to pay attention to in this situation is simply not to choose a pot that is too shallow, so that a certain space is kept between the base fertilizer and the roots.

New seedlings or small seedlings do not need additional topdressing during the first month after potting; just keep water and sunlight sufficient, as the plant cannot absorb too many nutrients during this period. So what can be chosen as base fertilizer for roses? My personal suggestion is that organic fertilizer or slow-release fertilizer is better, while chemical fertilizer is best used with caution or sparingly.

So-called organic fertilizer is simply some natural things that can provide nutrients to plants, such as soybean cake, manure, plant ash, and the like. One point to note here is that when soybean cake and manure are used as fertilizer for plants, they must be fully fermented before use.

A disadvantage of soybean cake and manure that have not been fully fermented is that they easily breed insects. By then, never mind whether there are nutrients or not, if the whole pot is full of insects, the roots are bound to suffer as well. Plant ash, however, is still a relatively natural and easy-to-use base fertilizer; its fertilizer effect is slightly lower, but it is simpler and safer to use, and especially for small seedlings, more plant ash can be used.

If soybean cake and manure are used directly, they are not only likely to breed insects, but also likely to burn the roots, which makes the loss outweigh the gain. The nutrient release of slow-release fertilizer is mainly closely related to temperature, that is, the higher the temperature, the more and faster the nutrients are released. So if you choose to change the soil in summer, when using slow-release fertilizer as base fertilizer, it is best to use a small amount and keep it away from the roots; otherwise, a large amount of nutrients suddenly released during the pot-settling period will cause fertilizer damage.

So I personally think that if repotting roses in autumn, using slow-release fertilizer as base fertilizer is better. Because after repotting, the weather gradually gets cooler, the fertilizer effect of slow-release fertilizer is released more slowly, and roses that have just been moved to a pot need a period of time to settle in and do not need too much nutrient supply. After a winter, the roots have grown stable, and the weather happens to be warming up, so the nutrient supply is relatively consistent with the growth needs of roses.