Another very educative write up. Thanks for the info. BTW, can we use the common green cabbage for this test or it has to be the red cabbage only.
regards

Hi Khalid (RoserianPk): I'm glad to hear from you. I miss your insights and questions which help me to dig for useful info. Without your questions in English Rose Forum, I would not had found the info. to benefit others.

Only red cabbage works. Litmus paper is based on lichen that changes color, but red-cabbage has a wider color range than litmus paper.

Boiling red cabbage in distilled water produces a hot juice which helps to dissolve the soil. It's very accurate if you let 1 large tablespoon of soil SOAK for at least 1/2 hour.

These are advantages of red cabbge juice over pH meter:

Does not need to calibrate, even the $200 pH meter needs recalibration before each use to be accurate.

Prolonged soaking released soil elements to yield the most accurate result. Coffee grounds is known as a buffer. Folks tested with pH meter reported wrong result of its being acidic. I tested coffee grounds in red cabbage juice, it's pink at first, but after 1/2 hour soaking, the solution became clear (neutral). Organic matter acts as buffer to neutralize soil, thus good for any pH.

You can test many samples of soil from your garden at the same time. I did that and found the hole fixed with pine bark (pH 4.5) became clear (neutral) in red cabbage juice. I found that decayed grass is slightly alkaline, versus my very alkaline rock-hard clay.

Below is an accurate color-changes in red cabbage juice, and its pH. If I test my soil when it's bone-dry, that's the result I get. But if I test my soil after it rains (pH of rain is 5.6), then my result is less alkaline.

Here is a link that might be useful:

There's a process called "Acid phosphatase" which cluster-roots secret acids. It's most efficient in sandy or fluffly soil, where roots can expand and get the oxygen needed. That's not the case with my compact heavy clay, where plants turn yellowish.

I have a rose seedling grown from seed. At first it's pale and yellowish in potting soil. After 7 months, it becomes green. It's planted in fluffy potting soil, which helps cluster root to secret acid in unlocking nutrients tie-up.

Here's a quote from the below link: "Some plant roots, especially cluster roots, exude carboxylates that perform acid phosphatase activity, helping to mobilise phosphorus in nutrient-deficient soils."

Below is my thornless seedling of Yves Piaget, picture taken September 13, in hot temp. above 90:

Here is a link that might be useful: Wikipedia on Acid Phosphatase of cluster roots

This post was edited by Strawberryhill on Sun, Sep 29, 13 at 11:24

Keeping the surface dry and alkaline helps with fungal prevention. Maintaining nature's balance of microbes helps roses to be healthy.

I found a blog by Cathy and Steve in Newburyport, MA, with 230 roses. They successfully use organic ways against black spots, see their blog in the below link, here are excerpts taken from their site:

1) sprinkle cracked corn.

2) "We began spraying with Rootshield, a patented formulation of Trichoderma in a wettable powder in the late summer of 2009. The results were dramatic and more effective than what we previously saw with cracked corn alone.

3) "Spraying regularly with our home made solution of peppermint or spearmint tea, canola oil, homemade garlic oil, clear soap, and other all-natural insecticidal agents helps to control not only blackspot but powdery mildew and insect pests as well."

4) "Because of our koi, we can't use pyrethrums in our garden either. For us, weekly spraying with either a garlic oil or mint based solution that includes baking soda adequately treats such pests as thrips, aphids, and spider mites and keeps a lid on powdery mildew as well."

Here is a link that might be useful: Cathy and Steve Garden with 230 roses

The role of soil bacteria in suppressing pathogenic fungi like rust and blackspot is documented by Penn State Extension on the use of Bacillus subtilis to protect leaves of Goldenrod from rust and fungal leaf spots.

Bacillus subtilis is a type of bacteria found on healthy soil, also in manure of animals that eat plants. It was used to treat dysentery in WWII. See link below:

Here is a link that might be useful: Penn State Extension Plant Pathology and prevention

This post was edited by Strawberryhill on Wed, Oct 16, 13 at 14:43

I recently tested the pH of the soil in the root-zone of roses affected by black spots in our non-stop late fall. They tested from neutral to slightly acidic, perfect range for black spot germination. Wikipedia wrote on how soil become acidic over time:

"Rainfall: Acid soils are most often found in areas of high rainfall. Excess rainfall leaches base cation from the soil .. . Additionally, rainwater has a slightly acidic pH of 5.7.

Fertilizer use: Ammonium (NH4+) fertilizers react in the soil in a process called nitrification to form nitrate (NO3−), and in the process release H+ ions.

Plant root activity: Plants take up nutrients in the form of ions (NO3−, NH4+, Ca2+, H2PO4−, etc.), and often, they take up more cations than anions. However plants must maintain a neutral charge in their roots. In order to compensate for the extra positive charge, they will release H+ ions from the root.

Some plants will also exude organic acids into the soil to acidify the zone around their roots to help solubilize metal nutrients that are insoluble at neutral pH, such as iron (Fe)."

Here is a link that might be useful: Soil pH - Sources of Acidity and Wikipedia

This is interesting and I might have to try this. Quick question to clarify instructions.

2 c. of beet water over 1 Tbsp of dirt? Or, can I use the 2 c. over multiple tablespoons of dirt?

Hi Zapod42: I'm glad to hear from you. Good questions. I put 1/4 to 1/2 inch. of violet juice above many samples. The details I wrote for English Roses Forum can no longer be googled. So I re-post here:

50 cents red cabbage and $1 distilled water. Rain water pH is acidic around 5.6 versus my tap water at pH of 8. That's why you need distilled water to boil red cabbage, resulting in a VIOLET solution. When I boiled red cabbage in my pH 8 water, I get a BLUE solution... shortcut to see if your water is alkaline or neutral.

I use tiny plastic cups and place samples in separate cups: 1 teas. vinegar (pH 2.2), 1 teas. baking soda (pH 8.5), 1 Tbs. of regular MiracleGro potting soil (pH 6.5), 1 Tbs. of peatmoss (pH 4), 1 Tbs. of crack corn, or crushed popcorn kernels (pH 4), 1 Tbs. used coffee grounds (neutral pH, a buffer, clear after 1/2 hour).

One tablespoon of soil from different locations in your garden placed in separate pre-labeled cups. Other indicator samples: pine bark (4.5), tomatoes (4 to 4.5), potatoe (5.4 to 5.9), whole wheat bread (pH 5.5), frozen cooked peas (6.4 to 6.7), cooked brocolli (6.3 to 6.5), cow's milk (6.4 to 6.8 pH), lettuce (5.7 to 6), cooked oatmeal (6.2 to 6.6), cooked rice (6 to 6.7), tea (pH 7.2), and egg white (pH 8).

You can also use freshly fallen leaves - See below: http://www.asecular.com/forests/phleaves.htm

Most acidic is Eastern Redbud (pH 4.3), Virgninia pine (pH 4.4), sugar maple (4.5), black maple (5.4), black walnut (pH 4.6), white oak (4.6), black oak (5 to 5.5), white ash (5.8 to 6.1), American Beech (5.8 to 6.9), flowering dogwood (5.5 to 6), Slipper elm (7 to 7.9), Hackberry at pH 8.

If the leaves are fully-decomposed over a year, they become slightly alkaline, pH 7.3, according to University Illinois Extension. Same with 100% decomposed grass, slightly alkaline.

If you test many samples, chop at least 4 cabbage leaves. Boil 2 cups of in DISTILLED WATER for 10 minutes, discard the solids. The purple juice works best when hot. Distribute the juice in cups, mix each sample with a spoon, and WAIT FOR AT LEAST 20 MINUTES.

If your soil is neutral, the juice will be clear like coffee ground or Organic potting soil (both are buffers, takes time to clear up). Most acid is fuchsia pink like vinegar. Dark pink is pH 4 (peat moss, pine bark, cracked corn and tomatoes). Medium pink is pH 5.5 (leaves, potatoes, and bread). Slight pink is pH 6.5 (MiracleGro potting soil, milk, oatmeal, and rice).

Light blue is slightly alkaline (decomposed grass or tea), medium blue is my 7.7 pH soil, dark blue is pH 8 egg white, more green is baking soda (pH 8.3), and bright green is wood ash at pH above 10.

Red cabbage juice has a wider range than litmus paper. It's more accurate than pH meter, since soaking allows the juice to interact with soil elements. Gracin from Florida posted a picture of how she did it, see below link:

Here is a link that might be useful: Cabbage juice soil test done by Gracin

This post was edited by Strawberryhill on Mon, Jul 28, 14 at 12:02

A quick way to test only a few samples: chop 1/2 cup of red-cabbage, put in coffee cup & fill with DISTILLED water. Cover lightly with wax paper, and nuke in microwave for 2.20 minutes. Let it sit for 10 minutes, then test your few samples. I use tiny fruit-cups, and pour the juice when it's hot, so it dissolve soil element better.

Great tip Strawbhill!

I finally found red cabbages, at a supermarket inthe south of Tuscany,but now I see that the purified water I have is "demineralizzata",not "distillato" (I am presuming that the former is dimineralized water,the latter distilled). It is advised for use in irons, car batteries,etc. Can I use this for this red cabbage PH test,do you think, or must I use only distilled? thanks, bart

Hi Bart: The demineralized would be fine, it's the minerals that raise the pH. I bought some "mineral water" and tested its pH with fish-tank litmus ... it was quite alkaline, around 7.6 ... but not as alkaline as my hard-well-water, pH 8.5, which leaves whitish deposits on my pots.

Demineralized water is even better than distilled water, I check on bottled-distilled water, it's pH is slightly acidic, like 6.8, rather than neutral. I have a de-humidifier in the basement ... its water is pH 7, neutral. Most likely it's the same as your deminerlizata-water.

Rain water is acidic. My rain water pH in my Chicagoland is around 6, but the East coast (near Atlantic Ocean) has more acidic rain, at pH 5.6.

OK, Strawberryhill, I did the test, but I think must've screwed something up:the water has remained exceedingly dark; black more than anything else! It seemed to me that six cabbage leaves were a lot for only 2 cups of water. Or perhaps I used too much soil in the jars? I plan to leave the samples for now, see if anything changes; maybe my mixture was just too dense???regards, bart

Hi Bart: I used 6 cabbage leaves with 2 1/2 cups of water, after draining off, it becomes 2 cups. I pour 1/8 to 1/4 cup of the juice over 1/2 tablespoon of soil. Mix with a spoon, and let it sit for 20 minutes. The juice above the soil will change either pinkish (acidic), clear (neutral), or bluish (alkaline).

If you use too much soil, then the mixture will be grayish or black. If so, let the soil settle down, after 1/2 hour, hopefully the juice above will show the color. Best wishes.
See below link for pictures of previous samples in red-cabbage juice.

Here is a link that might be useful: Red cabbage pH testing of many samples

This post was edited by Strawberryhill on Thu, Sep 18, 14 at 11:32

OK,I definitely had too much soil and too little liquid. The liquid is now a very dark grey-blue...means soil is alkaline,I presume?

OK,I definitely had too much soil and too little liquid. The liquid is now a very dark grey-blue...means soil is alkaline,I presume?
Looking at mine and comparing to the pictures on Internet,mine seems closest to around the ph 9 range;that is, slightly alkaline,but hopefully I'll get around to doing another test using less soil,and mixing with a spoon, too (I didn't do this before...) bart

Hi Bart: grey-blue means the soil is slightly alkaline, perfect for roses. The brighter the color is, the more extreme the pH. Gritty lime is BRIGHT blue, like the sky, at pH 9. Compared that to blood meal, grayish with a tinge of blue ... slightly alkaline, around 7.3.

Vinegar is BRIGHT shocking pink, pH 2 to 3. Compare that to my alkaline clay soil fixed with acidic pine park, just a touch of pink, but mostly clear, around 6.8 pH ... that's the place with the most black spots. Same with potting soil in rain water, when it's slight pink in red cabbage juice, means it's slightly acidic, perfect range for mildew and black spots germination. pH of rain is 6 in my Chicagoland, but much more acidic on the East coast, at pH 5.6.

The nursery's potting soil, or good potting soil, all register clear in red-cabbage juice ... they are neutral pH, means good buffering-action to neutralize the acid secreted by roots. Cluster-roots secret acid to utilize phosphorus from soil for blooms.

I bring up this thread: Most convenient: use bagged shredded red-cabbage. It takes 1 cup of shredded red-cabbage if you do 4 to 5 soil samples (about one plus 1/2 tablespoon of soil, and enough distilled water to cover it by 1/4 inch). If you do 10 samples from your garden, then use 2 cups of shredded red-cabbage.

I used rain-water (pH 5.6) to boil chopped red-cabbage, and tested many soil samples. The result corresponded well to the below chart, which I re-post.

Thank you, prairie_north, for an excellent document of red-cabbage testing. You are so organized and thorough. I admire your pic. My tap water's color is between pH 8 and pH 9, confirmed by fish-tank litmus paper.

"No. 3: soil beneath a rose with heavy black spot which starts pinkish and become bluish as time pass." That means the surface of the clump is acidic, perfect environment for pathogenic fungus like black spots. No.3-soil-sample turned bluish when the alkaline-solid part of the clump dissolve in water. That's what happened when I tested the rose park's soil. At first it's pinkish, then it became blue like my clay. They put sulfur granules in early spring, so those sulfur powder, being smaller particle, dissolve 1st, which gives pink. Then after prolonged soaking, the alkaline clay dissolve last, which changes to blue.

Another person with clay soil reported roses breaking out in black spots when she topped with alfalfa meal ... when that breaks down, it becomes wet and sour, thus caustic to surface roots.

I tested 6-months old white-pine-needles. The needles were old & brownish in color ... when I soaked in red-cabbage-juice, zero change in pH. Pine needles is an excellent buffer. Chicago Botanical Gardens use conifers-leaf-compost to mulch their roses: it's dry, fluffy, and neutral pH.

In contrast, pine-bark is major-acidic, became instantly pink just like cracked corn. Pine bark MULCH, when piled up, plus acidic rain, burns surface root with its acidity. However I got lots of blooms when I mixed pine bark thoroughly with my alkaline heavy clay ... pine bark, being acidic at below 4, breaks up my alkaline clay at pH near 8.

Coffee grounds is a weak buffer .... it became pink in red-cabbage-juice, and after 1/2 hour, became clear (neutral). I tested compost: it's alkaline (blue) at first, but as time pass, it became almost clear (neutral). Compost is a strong buffer, which offset pH changes.

Roses break out in black spots due to drastic change: too salty fertilizer, too acidic, as "souring" alfalfa-meal, or too alkaline, as quick-lime or alkaline-tap. Also a shift from equilibrium for water-level will induce black spots: too wet (poor drainage), or too dry (hot & dry weather). To keep a stable environment for health, a strong buffer on top is best, such as humus, compost, alkaline & composted manure, red-lava-rock, or dolomitic lime. At the same time, the soil beneath should be loamy & fluffy, plus slightly acidic for best phosphorus uptake.

It's OK to mix acidic stuff like "crack corn" or gypsum (17% sulfur) to break up clay months in advance. Cracked corn breaks down fast, and it releases humic acid & nutrients to enrich soil. I like it better than putting alfalfa meal in the planting hole. Cracked-corn is a firmer particle & better in breaking up clay. Corn has many anti-fungal nutrients: B vitamins, zinc, copper, calcium, plus fatty acids. Making the soil beneath slightly acidic foster mycorrhyzal fungi, both the ecto and endo types thrive at below 7. These beneficial fungi help roots with phosphorus-uptake, necessary for blooming.

For alkaline heavy clay, Dr. Huey-rootstock is best. Dr. Huey rootstock can go through my rock-hard clay better than my shovel, thanks to its root excelling in "acid-phosphatase". I saw Intrigue rose 100% healthy and lots of buds in a pot at Walmart, last day of July when it's hot & dry. That town's tap-water is reported at pH 9, very alkaline.

Due to our cold zones, own-roots is best. Sharifa Asma, Crown Princess Magareta, Queen of Sweden, Carding Mill, Scepter'd Isle, Pat Austin, Christopher Marlowe, Evelyn, Mary Magdalene, Radio Times, Golden Celebration are Austin roses that do well in alkaline clay, and winter-hardy. I don't winter protect those in my zone 5a, and their chance of winter-survival in your zone 3b is good, if the soil below is made fluffy, so roots can go deeper. Sharifa Asma and Pat Austin are compact and can be kept in pots, to be winterized in garage in zones lower than 5a.

No matter how alkaline one's tap water is, if the soil is fluffy & loamy, then roots can expand and do "acid-phosphatase" ... that's when roots secrete acid to unlock phosphorus-bind-up in soil. If the soil is heavy, then roots can't expand, can't secrete acid to utilize nutrients in clay. Coarse sand, gypsum, and chunky organics (leaves, alfalfa hay, cracked corn) fluff up clay, so the high pH doesn't matter.

I'm disappointed with Charlie compost in the planting hole, not impressed with Rose-Tone either ... but I'm impressed with cracked corn & gypsum: shiny leaves & more blooms. The trick to healthy rose is to make the soil loamy underneath for best root-growth and perfect moisture, but put many layers of ALKALINE buffers on top when it's rainy, and neutral buffers on top (alfalfa hay or conifer needles) when it's dry & hot.

Thank you for the very helpful information Straw. It's amazing how many times I have read or commonly heard "roses like acidic soil." There appears to be so much more to this.

Yes I noticed the cracked corn breaking down quickly. I left the samples to sit overnight. When cabbage juice was first added to the cracked corn, the colour was almost a bright pink. Now the next day, it is almost purple.

Below is the rose (a miniature) that is giving me trouble. It has lost 50%
of it's leaves due to blackspot. The blackspot is worst after it's first flush of blooms. I read somewhere this is related to nutrients the roses uses up to bloom? It had many large blooms for compared to the size of the plant.

I spayed it about a month ago
with sulfur, which seemed to stop the growth of blackspot, but once I
stopped spraying, it came back. I dislike the sulfur as it leaves an unsightly residue.

The bed around it was originally amended with peat moss, and has cedar shavings on top. Today I pushed the shavings away, dug up the soil around it, put down some sheep manure, and red lava rock.

It's funny, there is a bunch of the red lava rock around the house, we were thinking of getting rid of it as I generally dislike the looks of it, but if it helps the roses it now serves a new purpose.

Hi Prairie_north: Very pretty bloom on your mini-rose. Thank you for the l info. that cracked corn changed from pink (acidic) to purple (neutral) fast. I'm happy with cracked corn in the planting hole (did that last year), so is Momscottagegarden (clay soil).

I like what you wrote: "The bed around it was originally amended with peat moss, and has cedar shavings on top. Today I pushed the shavings away, dug up the soil around it, put down some sheep manure, and red lava rock." Peat moss mixed with clay becomes hardened a year later. Cedar shavings is acidic (pH 4) that would leak acid down when it rains (pH of rain is 5.6). Since mini-rose is own-root, the roots are nearer the surface, and is sensitive to acid leaching down. Own-roots do best with organic fertilizer, since it's nearer the surface ... some are wimpy like alfalfa sprouts, versus big-woody-bush-trunk Dr. Huey.

Red lava rock is a strong buffer at pH 8. I mulched roses with that during our wet months .. kept roses clean. Blooming takes up lots of potassium & calcium to make those firm petals. After blooming, potassium and calcium are both depleted, plus rain leaches out potassium & calcium & trace elements.

Red-lava rock in the planting hole, plus on top provide a continuous supply of potassium to prevent diseases, plus more blooms. Calcium is a strong buffer: I use that in many ways: as granular gypsum (calcium sulfate) to break up clay. If it rains a lot, I put gypsum on top of red-lava-rock. But for Dr. Huey-rootstock, I put dolomitic lime on top, since Dr. Huey likes it alkaline. Best ratio in hydroponics setting is equal nitrogen to potassium, 1/2 phosphorus, and 1/2 calcium.

I burnt a few own-roots with either salty manure in hot weather, or high-phosphorus fertilizer like bone meal. My best result in hot weather is alfalfa hay for nitrogen. Timothy hay is much softer, easier to mulch .. that's what I plan to test next. I got amazing result mulching with alfalfa hay in hot weather, best nitrogen-source ever, which beat anything I tested: blood meal, compost, Milorganite, alfalfa pellets, alfalfa meal, corn meal.

The problem with alfalfa in smaller particles: they gunk up on top, either souring, or hardening clay further. Alfalfa hay is fluffy, which cools and shade the roots in hot sun, plus it's a strong buffer: neutralize both acidic rain, and alkaline tap water.

Nice looking bloom prairie_northrose!

Thank you straw & jim!

Moved updated info. for 2016 into this thread:

I bought a soil-kit from Lowe's and it was a waste of time & gave me false result. Faster to get 7 to 8 leaves of red-cabbage from grocery store (sold by lb.), chop that up, and boil in 3 cups of DISTILLED WATER ($1 from grocery store). Boil for 10 min, then save the juice to test up to 15 samples, from potting soil, to alfalfa meal, to your tap water, plus 1 Tablespoon of soil from different locations in your garden.

The above test costs $2, $1 for distilled water, and $1 for red-cabbage leaves.

I use those small apple-sauce cups, or small yogurt cups for each soil samples. I use 1/2 tablespoon of baking soda as pH 9 and 1 tablespoon of vinegar as pH 2.6, plus red-cabbage juice itself as pH 7. I put soil samples in those tiny cups, then pour the hot cabbage juice. I use a spoon to stir each soil sample well. Wait for 30 min, before reading the color on top.

Here's the procedure in detail, inside the link the pic. of test tubes is wrong ... they accidentally switched pH 7 with pH 8 for the test tubes. My soil is dark-blue, at pH 7.7, professionally tested by EarthCo.

Coffee grounds should be clear, it's a buffer. Most potting soil becomes clear solution, or neutral pH. Alfalfa meal reported pH is 5.8. Rain water pH is 5.6.

The below recent pic. from the internet is most accurate:

One of my favorite posts.... I really need to try this as I always have red cabbage in the fridge.

bump up this thread for reference.

This is a wonderful thread! Thanks for bumping it up. I think it would be a very fun project for a kids science class too!

bump this up for reference.