I have concerns about the PH of my garden soil and on the advice of someone at a local garden centre, I purchased a cheap PH meter. I have used test strips and chemical soil test kits before and found them ackward. I was excited to try something that could give me instant readings in multiple locations. The meter was only $10 so I wasn't expecting great accuracy, but I thought the trade off between ease of use and accuracy/resolution seemed reasonable. I couldn't wait to try the meter out but when I went to use it I found that no matter where I stuck it in the soil, I got pretty much the same reading of 7.0. Hhhhm, I started to wonder if this thing was working at all, so I tried sticking it in water with a little vinegar. Right away the needle went down to 5.3. By the way, the soil I was testing was wet from recent rain and I did clean the meter off with a cloth after each poke. Does anyone have any feedback on how to get accurate readings with cheap meters? Can you really just stick them in the ground and get decent results or should I make up some liquid sample with distilled water? If the $10 meters are crap, can anyone suggest a decent, easy to use meter under $100? Will I be able to stick such a meter directly in the soil or do I have to prepare a sample?
I have tried the kit from Cdn Tire , with the same results. I eventually went to a pharmacy and just bought litmus paper. It seems to more accurate. Just a slurry of soil an water and a dip will tell you.
I find that the cheap meters can give you a rough idea of the pH. They work on an electrical conductivity basis. As for accuracy I wouldnt trust them vs a clinical machine but those sure arent cheap. For accurate testing you can try Norwest Labs in Langley or try checking with a local hydroponics shop or agricultural wholesale supplier like Terralink or Evergro/Wstgro, they may have a pH meter for soils that is afordable.
Dunc, litmus paper only tells you acid vs alkaline though, pH papaer will give you a more accurate reading although I have found it tough to decipher when used with a slurry.
I bought a cheap meter a couple of years ago and returned it. I had the same problem as you, it read the same no matter where I tested, even in soil that I had limed.
Thanks for all your feedback everyone. I bought a chemical test kit last weekend, the kind with the pills you put in a solution of water and sample soil. The kit confirmed what the meter was reading, so maybe the meter was right afterall. It's just that I thought our soils here in the GVRD area were naturally acidic. I am a little shocked to find out that all of my garden is 7.0 and 95% of my plants are acid loving. I have been in my house for over 5 years and not used lime anywhere except on the lawn. Strange. Who knows where the topsoil originated from though. Most of my plants are doing OK to fair, but I am looking for improvement in my PH sensitive plants (mainly Rhodos). Also, plants which should have glossy green leaves tend to look a bit pale and washed out in my garden, in spite of decent feedings of fertilizer, so I suspect issues with mineral uptake related to PH. Everyone I've spoken to at various garden centres has strongly discouraged me from applying "artificial" amendments such as iron sulphate, to acidify my soil. I know these are temporary measures. Still, I find this a little strange since they are in the business of selling the stuff. Other suggestions have been to encoporate peat and use acidic fertilizers, but there seems to be a lot of controversy on these two possibilities. Sounds like one can easily do more harm than good. I know soil testing is invaluable but I'm not sure I want to spend the money. Also, I don't know how homogenius the soil is so I'd probably have to take many samples to find out what I'm really dealing with. Since I know I'll be better off with slightly more acid soil given the plants I am cultivating, does anyone have any suggestions for a more natural and gradual but surefire method for lowering PH over say, a couple of years time? I heard pine needles are good, but it sounds like I'd have to use a truckload and then wait 10 years to see any results.
7.0 pH isn't too bad. You should be able to remedy that without too much trouble. There seems to be some controversy as to whether or not pine needles actually lower the pH. Try garden sulphur. Works much faster. The solution depends on how big an area you are talking about. In my former garden, with a natural pH of 8+, I ended up making a bed for my rhodies and other acid lovers---tons of peat moss and sulfur. It wasn't the best solution, but it worked pretty good. You have a less severe problem. And, of course, the use of peat moss is now controversial. I went to a lecture some years ago on growing rhodies on alkaline soil. The lecturer, whose name escapes me at the moment, insisted that the reason they are pale/chlorotic is that they are suffering from a manganese deficiency, not high pH. I was looking for my lecture notes, but I can't put my finger on them at the moment. All I can say is that he had fantastic rhodies. His recommendation was to use some tree leaves (of course I can't remember which) as mulch. He claimed not to use anything like sulphur or iron sulphate or peat moss. He apparently has done much research on this subject and is from Scotland, I believe. Perhaps someone can help fill in some of the blanks. I would be most interested in knowing the reasons why it was suggested that iron sulfate is not recommended as an amendment. Just a knowledge/interest question.
hortfreak, I came across that information just the other day. I believe you are referencing Professor David Rankin from the Department of Chemistry at the University of Edinburgh. He and some collegues were researching species of rhododendron which are commonly found growing in limestone regions in China.They found that rhododendrons are very effecient at grabbing and storing in their leaves all the manganese available and never seem to get too much. The manganese rich leaves when they fall and biodegrade around the roots get recyled back into the plant. Peat on the other hand, locks up manganese which is not good for the plant. I'm not clear if these lime tollerant Rhodos suceeded due to a genetic adaptability to lime or due to other factors in the local soils. The more I look into this the more confusing it all seems. Perhaps some other posters have additional insights.
No, it wasn't Prof. Rankin, although he may well have been party to the research. The man I heard was/is a nurseryman, I believe. The man could be from England, although my memory is that it is Scotland. Definitely one or the other. At the time I heard the lecture there were still many questions about why he was able to grow rhodies (not confined to species from China, everything he wanted) as well as he did. Apparently it was quite by chance that he discovered he could do so. I wish I could put my finger on my notes because I cannot remember the trees he mentioned. My memory (rather fuzzy) is that they were ash and willow, and perhaps one or two others. Does this make sense?
