Phalaenopsis fertiliser

[OzPhal]

Hi everybody,

I'm currently getting my head around all of these different fertilisers etc that are needed at various stages of growth of Phalaenopsis species. I've got some seedlings that I deflasked of P. lobbii they're currently in a compot with sphagnum moss as the potting medium along with some other species that are more advanced (9-10cm leaf span) - they're similarly planted in sphagnum moss. All compots/seedlings are in a heated proagation tray with temperatures in the range of 23 - 28oC and high humidity (there's also a computer fan to aid in air circulation to discourage mould). Anyway, I'm in Australia so I don't know how that impacts on the presentation of the data but I have a fertiliser that has the figures:

N 17.7%
P 7.9%
K 16.0%

plus trace elements of:

S 2.8%
Mg 0.06%
Fe 0.05%
Mn 0.24%
Zn 0.03%
Cu 0.02%
B 0.02%
Mo 0.0014%

I'm wanting to encourage vegetative growth to get the seedlings/compot established... would this fertiliser be suitable for the old 'weakly weekly' approach? I was going to apply 1/4 strength to the deflasked seedlings and 1/2 to the 9 - 10cm leaf span seedlings

[Ray]

I would use that fertilizer at about 0.5ml/L for everything, using it 3 out of 4 waterings.

Unless you water supply is hard, you might consider a calcium supplement, as well.

As a general thought, I am not one that thinks plants need different nutrition at different stages of growth. If you think about them in nature, the meager supply of food is more-or-less always available (hence my preference for frequent, light feedings over the monthly megadose some growers prefer), and it is the same for all plants in the local population.

If you want to encourage growth, raise the temperature and humidity.

[OzPhal]

Thanks Ray for your input - I really appreciate it... and i agree with you on the different nutrition arguement... especially when it comes to species...

Hardness is about 16 - 20 mg/L - what would you use to supplement calcium and is there a way to work out how much you should add?

In regard raising the temperature - would 28 - 30oC through the day be too much? should i drop it down at night? Should i keep the humidity consistent at, say, 85? or should i vary that between day and night too?

Thanks again

Originally Posted by Ray

I would use that fertilizer at about 0.5ml/L for everything, using it 3 out of 4 waterings.

Unless you water supply is hard, you might consider a calcium supplement, as well.

As a general thought, I am not one that thinks plants need different nutrition at different stages of growth. If you think about them in nature, the meager supply of food is more-or-less always available (hence my preference for frequent, light feedings over the monthly megadose some growers prefer), and it is the same for all plants in the local population.

If you want to encourage growth, raise the temperature and humidity.

[Ray]

Many paph growers sprinkle crushed oyster shell on the top of the medium to supplement Ca.

Phals are notoriously hot growers. That temp is a "walk in the park" for them.

I wouldn't worry about varying the RH.

[OzPhal]

Originally Posted by Ray

Many paph growers sprinkle crushed oyster shell on the top of the medium to supplement Ca.

Phals are notoriously hot growers. That temp is a "walk in the park" for them.

I wouldn't worry about varying the RH.

Thanks mate for your comments... so would you go even higher than that to encourage growth or will that be the best temp range?

[OzPhal]

Ray, would an N-P-K of 30-4-8 promote better/quicker growth? and what use rate would you use that at? The recommended use on the pack is 3g/L

[Ray]

That formula is awfully high in nitrogen, so will certainly provide for lots of growth, but it might stifle blooming, so I'd use it only during the "growth" phase, and a formula with less N starting a bit before when you might expect temp drops to initiate spiking.

3g/L????? Wow. You sure you didn't read the label wrong?

I know that 0.57g/L of a 12.9%N fertilizer I have will give the 75 ppm N level I use. 3g of a 30%N one would give 3/0.57 x 30/12.9 x 100 = over 1200 ppm N, and would surely kill the plants with excessive salts. The 1200 ppm is ONLY the nitrogen, and many plants cannot take a TOTAL dissolved solids level that high for long.

Doing that math backwards, 12.9/30 x 0.57 = about 0.25g/L, or maybe a bit more, is far more appropriate. I'll ask again - you sure that wasn't a recommendation of 0.3g/L?

[Neferet]

Well i'm using Miller's 20-20-20 for everything and 30-10-10 when i need the pseudobulbs to grow (both mixed with humus). I'm really interested in Ray's opinion on whether or not a plant would benefit with any other fert than the 20-20-20. I've seen the product he offers and i'm guessing it's what he uses ('Solo' fert) but does it really make such a significant difference in the way a plant grows and blooms compared to the 20-20-20 ?

[OzPhal]

Thanks Ray for that info... I wish I was wrong! The dosage guidelines say 15g/5L and oddly enough it's an actual orchid fertiliser - Campbell's B Orchid Fertiliser.

Here's a link to some product info from the supplier: http://www.campbellchemicals.com.au/...OrchidB-PM.pdf

[OzPhal]

It says on the PDF 'For Flowering' but it's a typo - the Yello formula (Campbells A) is for flowering...