As long as your soil is a pH of 7.0 or higher, additional liming is not necessary, provided the disease was not present previously. If so, liming 6 weeks before planting regardless of pH is suggested. FWIW, the disease is favored by soils with a lower pH but not necessarily guaranteed by such. I've grown all manner of cruciferous veggies in my slightly acidic soil without problems. And I have never applied lime. YMMV

seysonn, that's a good point you make. If neutral distilled water won't make a noticeable difference compared with tap water, then the only problem I have is finding a reliable way to test for pH. I thought my cheapo test strips might be off by a little bit, but the vinegar test does show them to be worthless. So what is the liquid test kit you're referring to. What brand is it?. I've been looking at better quality test strips, ColorpHast is a good brand (used by my scientist friend) , and also Phinex (4.5-9 pH range). I'd like to find some with a range of 2-9 pH so I can use vinegar as a low end standard. ColorpHast makes that range, but seems to be out of it every time I check. And does it matter if a test kit is labelled for saliva and urine...is that just because of the range, and can any pH test kit/method be used to test a soil sample? Any opinions on favorite pH testing methods? I think I'll start a new thread to ask that questions, or has this been done many times already?

Malcolm: thanks for the info. on pH meter. I checked on that before, and found that most of them are not accurate, and even the more expensive one above $200 need to be re-calibrated before each use. Red cabbage boiled in distilled water is quite accurate, since I am testing one agent against each other: color of Miracle-Gro potting soil is very pink, against the color of Scott's premium top soil with peat moss (greenish blue). I checked the colors of all 10 samples after 1 hour: peat moss gets even pinker, Scott's premium soil gets greener. Reg_pnw7: thank you for your feed back, my goal is to learn, and I don't need to be right, since I'm a newbie. Corn meal tested neutral, and the color of red cabbage boiled in my alkaline tap water is bluish purple, compared to the color of red cabbage boiled in distilled water, pinkish purple. If you google "optimal pH for fungi growth", there are several that cited preferably acidic for fungi growth. The red cabbage boiled in distilled water is an interesting experiment to test various materials. Try it and you'll see how accurate it is by testing with at least 10 mediums: few drops of vinegar, coffee ground, peat moss, baking soda, MiracleGro potting soil versus Scott's bagged top soil. The peat moss and MiracleGro potting soil get more pink after several hours, and the Scott's get more green. I used quite accurate fish tank litmus paper (Jungle brand from Walmart). It correctly gave a 7 for distilled water, and a 8 for my tap water. The direction said to read within the first minute - it took more than 10 minutes to get the epsom salt to dissolve, and this gave a more alkaline false reading at pH 7.3 to 7.5. However, when epsom salt is tetsted with red cabbage, this gave a correct neutral pH: the color did not changed compared with the control red cabbage boiled in distilled water. Blackspots can germinate on the ground and get splashed up by rain water. This year I have zero blackspots on 10 Austin roses mulched with very alkaline horse manure, as recommended by the British.

Yeah ... lots of critical things to consider such as initial and changing pH effects*, buffering, multivalent cations, anionic and cationic micronutrients, and zeolite like ion exchange surfaces on soil particles, which make it a play day for chemistry discussions. Then the attack and breakdown of plant and animal litter to slow release nutrients brings up neat microbiology and biochemistry aspects. Material science then decides to manipulate the situation with osmotic release and diffusion of encapsulated nutrients. And hydroponic principles try to partially play nature taking over the hydrology and lighting it up. Physics kicks ideas in there on this last aspect. For instance did you know that fluorescent light indeed glow when struck by energy (as you know), but much of the light intensity flashes through a series of distinct colors at 60 times a second? * Plants cheat neatly by manipulating ion exchange release of cationic nutrients. They knock off ammonium, potassium, magnesium, calcium and other positively charged ions by producing acid(s) to knock it off. H+ alone can cause the exchange but if the acid is on a small organic base (anion) like oxalate this organic can diffuse around and pull at the cations on soil that the plant wants and help knock it off, helping in the "weathering" breakdown of soil too. Chelators made by plants and microbes make it really interesting too. They diffuse around and hold certain critical nutrients so tightly that the plant has the choice of finding more, having a deficiency (specific nutrient starving), making a stronger chelator to take it back, and/or breaking the chelator down to free the nutrient. Now the fun parts ... the plant one might be considering is not be alone. A group of similar or different roots might be working together AND competing in that patch of soil, with different players at different depths Trees cheat and certain non woody plants cheat and go low. Moles, gophers and field mice run through this soil zone toox playing their games. No soil contact then no nutrient uptake, no root then no nutrient collection there for the plant, loss of stored nutrients and need to spend energy replacing the root. And there are smaller life forms co-inhabating the soil with the roots that are also directly or indirectly effected by soil pH. Let's put them into three classes as those that (1) don't generally effect a plant much, (2) can hurt the plant, or (3) can help the plant. Let's see ... hurting a plant is bad, unless it hurts a seriously competitive plant more. Helping a plant is good, unless it's again that serious competitor. Plants are not stand alone organisms in naturem. They live in community with microorganisms. So what if the soil pH helps support the growth of a microbe that can grow all over your plants roots? Sounds bad I know, but there are those three classes mentioned above. If your microbe is a pathogen that is bad. If it doesn't attack the plant but runs out and breaks down nearby leaf litter, great free food. It it doesn't hurt your plant but by being on root surfaces can compete with and stop pathogenic microbes from getting a foothold, great a free natural inoculation for immunity. There was a company called Eden Bioscience a couple decades ago here in the PNW that made an interesting observation. In large scale evergreen seedling production for forestry sometimes there were large scale fungal blights. Sadly alot of the seedlings all died at once in mass. However, sometimes there were a few seedlings near each other that did not succumb! In fact they looked totally healthy! When isolating bacteria, yeast and filamentous fungi from the surfaces of these plants they found that certain kinds could be grown in the lab that protected seedlings from attack, when sprayed onto them. These microbes grew best in their optimal pH range. They indeed colonized the plants, in this case leaf surfaces. And their presence did protect the leaves from pathogen attack. Obviously similar things must be happening in nature in the leaf canopy and also soil root zone of plants. So when a plant likes acidic pH 5 - 6 soil, is this just because nutrients are more available it? When I went to school, in what now seems like the dark ages, most plant physiology books focused almost solely on this. Or is it because beneficial microbes helping feed or protect the plant need that pH? My firm assumption is that both chemical and microbial pH dependent effects interact to make an optimum environment for that plant. And that some plants in the natural environment survive best, rather than grow best, at their optimal pH range. Why do many fungi sour (strongly acidify) what they are busy rotting? Niether competive microbes nor does the dieing plant tissue like it. The fungus gets more. This is exactly why you want to check the pH in the soil that you might be soon preparing for your new vegetable or herb garden this spring. Too basic, your plants starve. Too acidic, the pathogenic fungi don't starve. Then like the heirloom story of The Three Bears ... there's one pH that's just right.