nitrates in water

[banabo]

My well water is a good PH but I have 20 PPM nitrates in the water. I've read that nitrates are good for orchids, but I'm not sure if 20 PPM is too much. I have a variety--catt's, phalaenopsis, zygo, dendrobiums, onciduims, etc.

Can someone please advise?
thanks

[Ray]

20 ppm nitrate is a relatively high concentration for drinking water, but is what some would call an “ideal” level for orchid irrigation if you watered very frequently - every day or two. If you water less frequently, you’re still going to want to add fertilizer, but how much will depend on your actual watering frequency.

My general rule of thumb is to apply about 75 - 100 ppm N over the course of a week. If you fed and watered once a week, I’d add about 55 - 80, compensating for that in the water. If you feed once a week, but water once in-between, drop 20 ppm from the addition.

[Orchid Whisperer]

20 ppm nitrate is double the federal maximum contaminant level (MCL) for drinking water. Ok for washing, etc., not drinking, especially for children.

You might want to figure out why your well has such high levels.

[Subrosa]

Originally Posted by Orchid Whisperer

20 ppm nitrate is double the federal maximum contaminant level (MCL) for drinking water. Ok for washing, etc., not drinking, especially for children.

You might want to figure out why your well has such high levels.

High nitrate levels in drinking water almost invariably result from fertilizer getting into ground water.

[Orchid Whisperer]

Originally Posted by Subrosa

High nitrate levels in drinking water almost invariably result from fertilizer getting into ground water.

That is possible, but it could be from a septic system or similar source. Not fertilizer in a commercial/ agricultural sense, but yes, "nutrients". An old, shallow, or poorly-constructed well could matters worse.