When to apply fertilizer?

[Oscarman]

I have always applied fertilizer to wet plants (edit: plants that had been watered 1-2 days prior), being told that fertilizer will burn dry plant roots and the uptake of nutrients is better.

Any comments?

[littlefrog]

Saturated orchid roots cannot take up any more water, and your fertilizer is water soluble... So, I've always been suspicious of the 'water first' recommendation. Seems inefficient, at best. If I were worried about fertilizer burn, i'd fertilize first, and then water with plain water.

Rob

[frostedeyes]

i dont mind mine. i only use a "pinch" of fertilizer in a gallon of water everyday it works mine it grows and it blooms as well. (20-20-20).
* i dunno if it works coz i didnt follow her advice. she told me that to use pinch of high nitro in a gallon of water everyday when orchids are in active growth. Try to observe when the dendro canes are swollen (fat) then switch to blooming fertilizer again a pinch in a gallon of water everyday.

[Marissa]

I fertilize and water weekly weakly with a balance fert. I let the water run thru the pot first and fertilize after which I guess does not make sense if the roots can't take anymore water.

[DebsC]

I've always wondered about this, too. I could understand watering first if you were using a high concentration of fertilizer in your water. Then it might burn the roots.

But with orchids, using 1/2 or 1/4 strength, it really doesn't seem like it would burn roots at that ratio.

I'd hate to experiment and find out, though. That's why I continue to water lightly and then fertilize.

[markr]

I mix my fertilizer to approximately 150ppm N with almost every watering, hardly a weak concentration, and I never apply pure water first. Occasionally (every 5th watering or so) I flush the pots (no fertilizer), but I often forget to. Haven't noticed any detrimental effects doing it this way.

[Bolero]

I agree with little frog, as long as the fertiliser is diluted well and not to strong it shouldn't burn your roots. Once you water the roots cannot absorb anymore and that includes the fertliser you add later.

I've also heard that potting media like coconut and bark can make fertliser unavailable as they absorb the chemical. So even when the roots start to dry out the fertiliser might be sucked away by the medium. Therefore when I fertilise now I add a small amount to the watering can and that's it. I have never burnt a root yet.

[Ray]

30 or so years ago, it was common to feed infrequently, but with a strong solution. Thinking back, I'd guess it was about a 300-400 ppm N solution - maybe greater - on a monthly basis. You pretty much had to water first with that.

Now that folks have come around to a more steady, but more dilute application, there is no need, and has been said, is quite inefficient, because as the velamen become saturated with the water, it really cannot absorb much nutrient.

[Brooke]

I flush each pot with clear water and then go back and add the weekly weakly fertilizer solution. The flush washes out any salt build up and the fertilizer water is applied after the dry roots are awake. Since the fert solution is the last to hit the root, it is fertlizer the roots are absorbing.

I'm also too cheap to use that much fertilizer to saturate the container :>)

Brooke

[Leisurely]

I have never experienced a fertilizer problem by using 1 tsp. per gal. and I have been doing it for years without watering with clear water first. I suspect if the water being used in high in dissolved mineral salts and you combine that with the fertilizer salts you could end up burning the roots. Vanda types are an exception to the weakly, weekly. They respond quite well to 1 tbsp. per gal. because they are heavy feeders.