watering

[sept2256]

I would need a tip about watering tecnique. I usually water once or twice a week with fertilizer and, once a month, with only abbundant tap water, to wash the substrate. In your opinion, after this last operation, have I to immediately empty the pot and re-fill with fresh fertilizer or I simply have to leave the tap water in the reservoire till next watering?
Thank you!!
Pierangelo

[Lene Th.]

Hm... i got a bit confused by your post... I fertilize once a week, i let the pot stand in water with fertilizer about ten to fiftheen minutes, and let it drip of. In the reservoir i use only clear water, exept the small amunt that may drip of the leca into the reservoir after the fertilizing-bath.

Though im just a newbee, and i havent got the clue about fertilizing, exept that it is about feeding my chids, they still seem to be a very happy bunch!
I have 15 phals, one Oncidium/Cambria-mix/whatever and one Dendrobium i just got... and now i have one phal in bloom, second time this year, tree other phals with spikes, alsow second time, exept one that was a rescue, and the Oncidium/Cambria-mix/whatever has a spike as well
The others have all gotten severel new leafs and are growing roots like crazy...
I dont know anything about fertilizing, but they seem to like my way anyhow.

[Ray]

I have fed my plants at every watering for more than 10 years, and if I fill the pot rapidly to the top - before the reservoir dries out - I see little-to-no buildup.

If you do want to plain-water-flush occasionally, I don't think its an issue.

[sept2256]

ok, It seems that the easy way is always the right way!
Thank you all,
Pierangelo

[Ray]

That depends on the full set of parameters of "easy", doesn't it?

I water a couple times a week (on average) with a 125 ppm N fertilizer solution in a warm, humid greenhouse. If I increased my fertilizer concentration, I would likely see more rapid mineral buildup, so would have to flush with plain water often. Likewise, if my growing conditions were drier.

[sept2256]

Well, but let me understand.... is the mineral buildup a problem for chids or it is just unaesthetic?
In other words, I don't have very good coltural condition (open air in the hot period, like now, and in house during cold months). if I water with fertilizer 250 ppm, could it be a problem for chids' health?
Thanks, Pierangelo

[Ray]

The flow of water and nutrient ions into and out of a plant occur in large part due to osmotic pressure. In other words, if there is a gradient across the cell wall, the natural forces will try to even it out.

If you allow a significant amount of mineral buildup to occur, that means the nutrient salt concentration outside the cell is VERY high, while the water content is very low. So, water is drawn out of the cells (not good) and the salts are drawn into the cells at a very high rate (also not good). The typical result is dead roots.

By the way, when I stated earlier that I use 125 ppm, that's the nitrogen concentration only. The total in most fertilizers will be more like 700 ppm at that dose. Double it and it can stress the plant.

In the old days, it was common to feed heavily but infrequently. It seems to me that often and more dilutely is far better. Done right, the plant actually absorbs more nutrition and grows better.

[sept2256]

perfect and clear!!
thank you, Pierangelo