Fertilizer - when to start?

[Maty]

I just repotted Cattleya seedlings in orchid bark. When should I start fertilizing them and how often?

Thanks, Maty

[jerrymeola]

You can fertilize young orchids almost any time, but go easy. The younger the plant the less you use.

Keep in mind that all plants, including orchids, can not absorb inorganic fertilizers. The chemicals have to be broken down by microbes in the medium into a form usable by the plant. So when using new medium that may be sterile - go easy. The plant may not absorb it and buildup will hurt the plant.

You say seedlings but that means a wide range to whoever is reading this thread.

True seedlings are usually meant to mean Flask, compot and some stretch to include 1 inch plugs. These seedlings, because of the small roots and lack of significant pseudobulbs, need to be kept fairly moist and not allowed to dry out completely. I do not put seedings in a regular bark mix as it dries too fast for me.

5-8 inch tall Cattleya, pot sizes 2 1/2 to 4 inch can be grown in a fine bark mix. Only older mature plants do I put in medium bark and I never use large bark.

[Maty]

Thanks Jerrymeola. If you were repotting small Cattleyas, came in 2" pots with s. moss, longest leaf length about 5", what size pot would you use? I think I lucked out and got the right size bark. I'll try a little diluted fertilizer on the plants that have lived here about a month.

Thanks for replying to my post. !

[Kevin Western]

Originally Posted by Maty

I just repotted Cattleya seedlings in orchid bark. When should I start fertilizing them and how often?

Thanks, Maty

Hi Maty,
Running a large orchid tissue culture lab plus a full time 9-5, 5-7 days a week job I don't get many chances to fertilise properly.
For a long time my plants have survived but they were obviously hungry.
In desperation I have taken to just tossing a small amount of the slow release, encapsulated, broad spectrum fertilisers such as Osmocote, macrocote, Nutricote etc on top of pots that I have no chance to repot and the results have been quite satisfying. The last 2 growths that an old spindly cattleya put up since I applied the 9 month slow release Macrocote with trace elements are at least equal in weight to the whole of the rest of the plant.
I deflask a lot of seedlings and clones and in such genera as dendrobium, cymbidium, zygopetalum and the oncidium alliance I used to have very slow growth but since potting up with a small amount of the above fertiliser + some pelletised, roasted chook manure the growth has been spectacular straight away. The trick as others have said is not to overdo it but fertilise you must or the microbes in your growing medium will take all the nutrient and the seedlings will starve and will find it difficult to survive. In reality, growing orchids really well is a matter of getting a whole lot of culture factors close to just right.
Kevin Western

[Kevin Western]

[quote=Kevin Western;17006]

Hi Maty,
Running a large orchid tissue culture lab plus a full time 9-5, 5-7 days a week job I don't get many chances to fertilise properly.
For a long time my plants have survived but they were obviously hungry.
In desperation I have taken to just tossing a small amount of the slow release, encapsulated, broad spectrum fertilisers such as Osmocote, macrocote, Nutricote etc on top of pots that I have no chance to repot and the results have been quite satisfying. The last 2 growths that an old spindly cattleya put up since I applied the 9 month slow release Macrocote with trace elements are at least equal in weight to the whole of the rest of the plant.
I deflask a lot of seedlings and clones and in such genera as dendrobium, cymbidium, zygopetalum and the oncidium alliance I used to have very slow growth but since potting up with a small amount of the above fertiliser + some pelletised, roasted chook manure the growth has been spectacular straight away. The trick as others have said is not to overdo it but fertilise you must or the microbes in your growing medium will take all the nutrient and the seedlings will starve and will find it difficult to survive. In reality, growing orchids really well is a matter of getting a whole lot of culture factors close to just right.
Kevin Western