Beginner Growing 5 Phals, 2 Vandas, 2 Catts, 2 Dendrobs, 3 Oncidiums -$35 shop light

[cluelessmidwesterner]

I just finally got an answer back from my local city water utility.

Quote: "The average hardness last month was 7.2 grains. Hardness varies throughout the year from 7 to 10 grains/gallon"

When asked about total dissolved solids - Quote: "We don’t test for Total Dissolved Solids so I don’t have any values to provide you for that." (insert eye roll here)

I guess I'm mixing RO/Rain/distilled water with my tap water. The question is at what ratio.

[Roberta]

Originally Posted by cluelessmidwesterner

I just finally got an answer back from my local city water utility.

Quote: "The average hardness last month was 7.2 grains. Hardness varies throughout the year from 7 to 10 grains/gallon"

When asked about total dissolved solids - Quote: "We don’t test for Total Dissolved Solids so I don’t have any values to provide you for that." (insert eye roll here)

I guess I'm mixing RO/Rain/distilled water with my tap water. The question is at what ratio.

If you want to know the TDS, invest in an inexpensive meter (and a calibration solution for it, so that you'll know that it is working correctly) Then test your water now and then. Many water companies get their water from multiple sources, so TDS is highly variable. (Mine may be 180 ppm on a very good day, 450 on a very bad day, average usually in the neighborhood of 250.) You don't need to stress over exactly what you're using on the plants, but knowing what you have would give you a better idea of how you want to mix it with pure water. The other consideration on using part tap water is to have some idea of what minerals comprise that TDS... if it is mostly calcium and/or magnesium carbonate/bicarbonate, most plants can tolerate it quite well (and benefit from the calcium and magnesium, which are necessary in modest quantities) If it is sodium chloride (salt, as one would get from sea water intrusion) then you would not want to use it on your plants. That info should be in your water analysis.

[annie.exe]

Thought I'd post an update after trying to take your advice and upgrading my setup a bit.

I think they've all definitely improved! The bare rooted Cattelya and Dendrobium are now potted in an orchid mix (bark, lava rock, etc) with just like two strands of spagnamoss mixed in there. The Vandas are now in clay pots with just a few strands of spagnamoss next to their roots.

I added a humidifier and upped my humidity from about 28% to around 40%.

I went to my local Orchid nursery - Orchids Limited in Plymouth, Minnesota and the owner helped me pick out 2 new LED bulbs. These are the ones I got: https://www.orchidweb.com/supplies/l...00-5000-kelvin The owner told me to put the lights 5 feet above my plants so for now I'm just rolling with that.

I also got a (in my opinion) nicer looking shelf from Menards.

I still have a lot to learn but I think that they're improving! Thanks so much for all your help!

[Orchid Whisperer]

Originally Posted by cluelessmidwesterner

I just finally got an answer back from my local city water utility.

Quote: "The average hardness last month was 7.2 grains. Hardness varies throughout the year from 7 to 10 grains/gallon"

When asked about total dissolved solids - Quote: "We don’t test for Total Dissolved Solids so I don’t have any values to provide you for that." (insert eye roll here)

I guess I'm mixing RO/Rain/distilled water with my tap water. The question is at what ratio.

For TDS, you can ask them again if the utility measures electrical conductivity (EC), also known as specific conductance (or conductivity). EC is usually reported in units of micro Siemens per centimeter (uS/cm). All any TDS meter does is estimate the TDS (in parts per million; ppm, same as mg/L) from EC, using a simple calculation. You can find the "how to" instructions for doing the calculation here:
How to Calculate Total Dissolved Solids: 10 Steps (with Pictures)

Spoiler alert: the formula is: TDS =[KE] × [EC]


Note that the calculation includes a "correlation factor", KE, which varies from 0.55 to 0.8. The KE will vary depending on the characteristics of your water. The KE of well water from northeast Georgia, well water from Chicago, sea water, rain water, tap water, lake water, pond water, and Okefenokee Swamp water, all will likely be different. A TDS meter has no way of knowing your KE, so the meter probably has a built-in "guess" for KE. If you have a measured EC, do two calculations using KE = 0.55 and 0.8, assume your water is somewhere in that range. A measured EC of 275 uS/cm has an estimated TDS between 151 and 220 mg/L (calculated), for example.