About slow release fertiliser in pellet form in a pot plant.

Here in the UK when you buy a plant in a pot a lot of them have slow release-fertiliser in the form of small orange beads, sometimes glued together into a cone, inserted in the compost. You can also buy more fertiliser in that form. I have noted that years later the beads remain intact and the same color and size. So I presume that the bead itself is not bio-degradable (If you crush a 5 year old one it becomes a white insoluble powder). My question is. If there is no visible change in appearance as the fertiliser is released how can you tell when it is used up and you need to add more?

When you buy a package of such fertilizer it should be labeled how long it lasts under normal conditions. Normal conditions is an average amount of water and warm enough temperatures for the plant to be growing. I would put the first dose in ahead of the season so the rain starts dissolving the fertilizer so it is in the soil when the plant is ready to use it. Then follow the directions about when to apply more. Stop well ahead of the cold season so the plant can harden off and be ready for the cold.

Each time the water passes the fertilizer pellet a little bit of fertilizer dissolves through the coating. Eventually the pellet is hollow, as you have seen. But you do not have to wait until they are all hollow to add more. That is the way to tell, though, when you buy a plant with these pellets. You have no idea how old they are, or what the life span is. I would add more when about 3/4 of the pellets are hollow. The rest might still have a bit of fertilizer, but not much.

Hi Davis2000, I agree with you that these type fertilizers are a bit too unpredictable for my own use and personal experience. When I do buy a plant in a pot that has these clumps of beaded so called slow release feeds, I remove them soon as possible, Personally I would repot the plant also and use my own shop bought (BRAND NAMED) compost that is mixed specially to suit the type of plants I am potting, as I use the compost, I add my own slow release plant food, my preferred type is Blood/Fish/Bone as this is a natural product and is slow release, second choice would be pelleted chicken manure, then depending on the type of plant I might use a little multi purpose feed, all these are brought at the garden centre BUT, you must use any type of fertilizers / feeds with care as too much can be as bad as none at all, just go by the dosage given by the makers directions in fact normally for my first feed, I would use half the doze and keep an eye on the plant to make sure they are OK then give full strength when required after that.

I would imagine after a season with these clusters of fertilizers it could be taken thet the fertilisers have been washed out from the pot / soil but again, without knowing how long these pellets or clusters have been present in the pot, how on earth can you tell, therefore I will just continue as have for many years, just remove them for peace of mind.

Hope this gives you food for thought and maybe others will come in with ideas that they have too.
Best regards. WeeNel.