ph values & gardening books

I swear I thought I posted this but can't find it now. One of my pet peeves about gardening books is not including the optimum ph for each plant. Does anyone know of a gardening that has that. Perhaps some encyclopedic kinda book. Organic Gardening's Encyclopedia has a list of those that like acid and those that like soil to be alkaine and then everything else is supposed to like neutral, but it's not nearly comprehensive enough.........

This message was edited Friday, Sep 13th 8:10 PM

This message was edited Saturday, Sep 14th 7:35 AM

Woodspirit1: I've been wondering the same thing. Sorry I don't have any answers for you, but I'm going to be watching this thread. Thanks for posting.

Scanning Google I found 3 incomplete, but never the less, important sites. If one was to put them together in Favorites, a good colection might occur. There must be others.
http://homeharvest.com/plantphpreference.htm
http://www.calpoly.edu/~agmesa/soil/plant_ph.html
http://homepages.which.net/~fred.moor/soil/ph/p010601.htm

This message was edited Friday, Sep 13th 10:37 PM

This message was edited Saturday, Sep 14th 12:19 AM

Good research, Golddog! These are really helpful. There are lots of unlisted soil ph's in the PDB, and these sites will be really helpful...Thanks!

Part of the reason optimum Ph isn't listed in a lot of books is because its too specific and sometimes misleading to add a Ph value. The majority of plants we grow in the garden prefer a slightly acid or neutral soil which are the most common soil Ph values. These plants are obliging enough to tolerate much more than neutral and slightly acid which means they are easily grown in a wide range of soil Ph values.

The only problem comes when you have specialist plants from certain areas, like species from certain parts of Japan or Limestone Alpines. Even then these plants will tolerate quite a range of Ph with in acid or alkaline.

Well, what brought this up was the folks that raise bruggies questioning it. It's beginning to look like they need something a bit "sweet"

The Southern Living Garden Book lists whether they prefer acid or alkaline soil if it's important.

Baa, then why is this our only reference to soil requirements/preferences in the database?

Well, if I recall rightly I was one of those (or maybe the only one) who requested Ph values to be included.

I felt that it was important to identify the plants which would require the more extreme Ph values such as Dianthus and Rhododendron. I know a lot of people who buy heathers and heaths each year only to find them dead by summer because they live on a chalk ridge. I live in a predominantly acid soil region, 15 miles north it's predominantly chalk so the garden centres stock for both and give very little clue to the unwary and new gardeners as to the soil requirements, I'm sure Hampshire is not unique in this.

Knowing the Ph values (sic) of your soil is important to allow people to make good choices for their garden and for the correct placement of plants. I've noticed some of the newer books have cottoned on the Ph values and are sometimes strict, they are of course, giving an optimum Ph value which isn't always necessary. Nothing to do with a living being is set in stone but the guidelines should be in place.

The Ph values aren't the only soil requirement options on the PDB, there are options for constantly moist soil, suitable for bog gardens and suitable for xeriscaping.

Well perhaps the optimum is too specific, but a range would be nice. Cala, thanks. I don't have that book but will certainly look for it. Our library has a book sale coming up. The whole community gives books for this sale and the proceeds will go to the new library which we hope to open in 2005. Lots of garden books show up there.
Baa, I would love to know the meaning of the work Cotton that you used here. In the southern parts of the U.S., when you "cotton to" someone or something, it means you have taken a liking to it.

Yes, Baa, you are correct about other options, but they only refer to moisture levels, as I recall. I find myself either checking average needs or not checking anything at all in this area. I also hesitate to use the term "boglike", since our whole environment around here is "boglike".

I guess I have a hard time leaving blanks on the PDB, but I suppose it is best sometimes. In the case of "Other Details" and I have a problem with the drop-downs. How can you offer details with drop-downs?

Woodspirit

Sorry I forget about the vernacular being different sometimes, cottoned on to here means to have caught on to something, came to understand.

WZ

With the exception of Ph values and moisture requirements, what else would you like to see there?

In my experience it's only bog like when you can't stand on it without sinking ;) The place to offer specific details is the comments box in my understanding, it's where I put them anyway.

Baa, I try to help the customers with the plants that have specific needs. If they bring a lavender plant to the check-out, I remind them that it needs well drained, alkaline soil. This is best accomplished by adding a handful or two of gravel(the regular driveway kind) to the hole at planting. Little things like that help them keep their plants alive.

To put in my two cents' worth, I agree that we're often (mis)lead by garden writers and others, into believing that a plant requires a very tight pH range in order to perform at its best, when the vast majority of plants are quite happy in a fairly wide range of soil pH values.

And when we decided it was a good idea to add pH values to the PDB, I think we started out with three or five very broad ranges (you know, alkaline, neutral, acidic, or something along those lines :)

But after some debate, it was decided that it was better to have more (and more specific) ranges, although multiple ranges can be selected for plants that can tolerate a wide range.

To answer some of the other questions about the current (and possible additions) to the attributes in the PDB, I am always open to adding more checkboxes if it's decided that it's something that people will likely need to select a plant based on.

For example, it's highly likely that someone would like to see all yellow-blooming, variegated plants that are hardy to zone 5 and require average moisture.

It's also plausible that some gardeners will want to search for plants that have a pH within one or two of the ranges we specify, because that's what they have to work with.

If there are other details that would likely help gardeners in their search for the perfect plant, please toss them out.

One caveat, though: the bigger the PDB gets, the more unlikely it is that others will go back through and add the missing information when new checkboxes are added. So if you're lobbying for something else to be added, please ask yourself if you're willing to spend the time going back through thousands of entries to check the correct box(es) for each entry. That's not to say you're automatically tasked with this chore, but it's a good "reasonableness check" and should be taken into consideration when proposing additional checkboxes. (Cuz SOMEBODY'S gonna have to do it, sooner or later :)

I would just like to add that I personally am Neutral on these contentious issues (kikisdad = ph 7.0)

Ha Ha Ha I think I will have my ph tested next week!

Cala

Your customers are very lucky to have you as you're so knowledgeable about your plants :) Here we often get some dribbly nosed teen, just learning the ropes.

Vols

You raise a good point about the checkboxes. Some plants are being added with virtually no boxes checked which is a pity because they may get lost in the PDB over time.

Well, this turned out to be a very informative thread. I did have fun with one dribbly-nosed kid at Kmart however. He was appalled when I told him you could dip your hands right into Black Kow and sprinkle it about. But he was cute and smart and began to question me. I told him that a pet peeve I had was that kmart and Wal-Mart both let so many plants die. And the checker never recommended fertilizers or other additives that help specific plants. He started really paying attention, grew a few of his things that summer and now he's in horticulture school.
Evert's never been dribbly-nosed, but I sure hope he goes into horticulture and/or landscaping...

When posting to the PDB, I come across lots of blanks, and I fill them in when I can. Sometimes, when most of the blanks are empty, I think someone has a good photo, but no info to offer. I'm sure there are plenty of gardeners out there that have the info, but not the photo.

When I come across an entry begging for a photo, it has occurred to me to start a thread in the appropriate forum asking for photos of this particular plant, adding a link to the page in the PDB for that plant. The same could work when info is needed. What do you guys think?

Wonderful idea, Weezin! In fact, I've been known to outright grovel for people to post photos that I see in the hydrangea, daylily, hosta, veggies forums. I'd love the assistance :)

And I'm still mulling over the best way/time to launch a mid-winter "fill 'er up" challenge that is aimed stricly at completing existing entries with details, details, details. Maybe offer incentives for ratings and photos, but the thrust would be to work on what's in there, not adding new plants, for sure.

Well, it's a tough call, Go_vols, since I'd hate to see people hesitate to add new plants, but every new unfinished entry is one more job to do, I guess. I think it would be wise to do any alterations to the format ASAP, so there is less editing to do later. Here's an area that I still think needs some work:

Other than comments, there is no area for description of the plant. If one uses this method, the next comment will become the top entry and the original entry will drop to the next spot. I know we are not all necessarily great authors, but I'd like to see written descriptions of the plants. Then we could do away with some of the "Other details" options, or just let people opt for either one.

Is there anyway to get info on how much heat a plant will tolerate? PH values vary for different spots within small areas, like a average size yard. The county extension test proceedures say to get several samples from different spots and mix, that supposedly makes the test result an average of your soil's PH. Is this "average" value of any use?

debsbloom, the AHS has a heat zone map, and some plants have been given heat-tolerance zone designations. Here's a link: http://www.ahs.org/publications/heat_zone_map.htm

Debsbloom

I can see the thinking behind the average Ph value BUT one of the reasons you take soil samples from several places in your garden is to find the differences within the garden. For instance we have neutral - slightly acid soil. Knowing where the acid and neutral spots are allows me to plant accoringly and has also enabled us to grow Dianthus to some degree of success in the neutral spots. To mix up the soil samples is just giving a wide overview with little detail.

Yep, to tag onto Baa's comments - the extension service here tells residents to do a mix only if you are wanting to sample your entire lawn. Otherwise, they recommend that you take separate samples for each flower bed and tell them what you have in the bed, so they can recommend additions that will help those plants the most.

Our extension rep strongly suggests soil sampling, but I've never done it. The main reason is that we have no "soil" here. What we have is ground rock or glacier silt and whatever composted materials that might make up the first two or three inches of planting surface.

Due to our cold soil temps, most gardening is done in raised beds or containers. Soil is generally purchased by the truckload, originating from the Matsu Valley (north of Anchorage) or occasional local pockets of soil made available around here. Otherwise, we "make" soil by composting, etc.

So, you can see the problem with soil sampling. If you buy a belly dump of soil, that could be tested, but all the combining, mixing, etc. is still an unknown factor. For our container plants, we mix soil by the wheelbarrow load, and in the fall, we dump it all back into the soil pile...another unknown factor. Soil samples must be sent by mail to the lab that is some 150 miles from here. Results are slow, and the testing runs over $20 per sample.

Generally, I just watch the plants to see what they might need in the way of ammendment. Foliage discoloration, etc. is often a trouble sign. I use wood ash to sweeten because it it "quicker", and I use peat to bring up the acid when necessary.

We just use a simple kit costing a couple of £s and distilled water (since our tap water comes from the chalk hills).

I've got one of those kits, Baa, but I've never used it. I'll have to give it a try on some of the containers DH filled this year. He's been doing the "mix", and it seems that it might be a bit acidic. Some of my plants began to get a celery green tinge with darker veining in the leaves. In all fairness, the mail in soil testing is much more extensive than just pH levels, but pricey if you have lots of sampling to do, none-the-less.

Calalily
Zone 7a
Sep 14, 2002
8:39 PM
Baa, I try to help the customers with the plants that have specific needs. If they bring a lavender plant to the check-out, I remind them that it needs well drained, alkaline soil. This is best accomplished by adding a handful or two of gravel(the regular driveway kind) to the hole at planting. Little things like that help them keep their plants alive.

Thanks, Cala.

I had to bring this back because I want to grow alot of Dianthus in a big hurry. And have been searching and searching...Page 4--I think. Will this work right away? If you don't have this gravel, where can you get a couple handfuls? Gee, no wonder my Lavender died! Does it supply the sweetness too? Lime takes too long doesn't it? Does it work for Brugs as well?

This thread needs to be continued.

Thanks, Vi

This is an interesting thread. This is what I use to test soil and compost pH:

https://www1.fishersci.com/index.jsp

The test works in under 15 seconds and is certainly precise enough for non~laboratory purposes.

The idea of "optimum" pH for plants might best be applied to commercial greenhouse applications, such as tomatoes, where the environment can be completely controlled.

In our gardens, where life is a little less precise, I am thinking that we might have to be a little more broad minded.

Overall, what I have been trying to do in the plot I garden..., a former construction site with all the issues you can imagine..., is simply get organic matter into the ground. My applications of compost and other organic ammendments average pH 6.5.

What I would be interested in knowing is..., when we control pH in our soil and our compost, exactly what is it we are trying to control in plant metabolism?

Adam.

Aotearoa

We aren't changing or controling anything in the plant when we try and manipulate soil pH, we're simply trying to make the soil nutrients more available to the plants.

We can't change the metabolism of a plant through pH amendments. In fact it's quite hard and takes a fair few years for the soil to register a fairly small, constant pH change and even then it might only ever be temporary. This is why some people lime the soil year in year out.

pH does affect the nutrient, microbial and mineral availability in the soil, the pH (potenz Hydrogen) as I'm sure you know, depends on whether the water in a substance, like soil, has a majority of positively charged Hydrogen ions or negatively charged. These ions play a part in dictating which nutrients are released in the soil and which are kept largely unavailable or 'trapped.'

Plants that have adapted to extremes of alkaline or acid soils are few and far between, they tend to need less of the nutrients that are 'trapped' by either the acid or alkalinity of the soil. For instance, Dianthus species tend to thrive on calcium but need little iron, alkaline soil easily releases calcium but traps iron. Rhododendrons, need iron and less calcium, on an alkaline soil they suffer from iron deficiency (Iron chlorosis). This isn't to say that alkaline soils are deficient in iron (they can be but not always), merely that iron isn't as soluble in the Hydrogen portion of the soil water due to the ion charge and is therefore generally unavailable in that pH of soil.

The majority of plants prefer a more neutral soil because strong pH soils also tend to trap an amount of nitrogen, phosphorous and potassium as well as the lesser known (but often equally important to plant health) minerals like manganese and magnesium. Plants which thrive in strong pH soils also tend to prefer poor nutrient soil and don't need large scale applications of FYM (farm yard manure if that's not a term used elsewhere in the world) et al.

pH can also affect which diseases a plant can suffer from, Brassicas are known to suffer from club root (Plasmodiophora brassicae), the risk of this disease is lessened in alkaline soils and can be prevalent in acid soils where Brassicas have previously been grown. While the cabbage will happily crop in an acid soil, it's much less likely to suffer club root in an alkaline soil.

These are just some of the reason why knowing the pH of your soil is important to your plants' health.

You will probably never see as many gardeners liming their lawns and gardens as here on the North Shore of Vancouver, B.C.! Reason, being, is we live at the base of mountains. The mountain side, at one time, completely treed...the residue is naturally composted(acidic).....thus the need to build up the soils ability to cause plants to uptake nutrients easier! Having resided here for over 37 yrs now and gardening for really, 30 of them, I have found that constantly trying to build up a pH of more alkalinity as opposed to acidity is useless..so as Baa has said, each specific plant has individual needs!....especially roses...there was a time I covered dthe garden with Mushroom manure(lime included)........since a number of years now I use bagged animal manure!!!!!!! much better performance! When I lecture on Roses and give planting clinics, etc. I have always covered my back and this, is my favourite saying....."Nothing is written in stone". E.

I just love reading this sort of exchange..., people who have both knowledge and experience laying out their thinking.

About 70% of my garden plot is as bare as beachsand and about equally as fertile, with a cation exchange capacity of 8.5 (notice, I didn't say pH).

The 8.5 number essentially means no nutrients are available to be exchanged as positively charged ions, regardless of the pH.

It's my challenge as an urban gardener to work with what I have and see what I can help grow in it over time. I am coming up on a big decision...,

Do I take off the top few inches (several cubic yards of dirt that I will have to move alone and by hand), or slowly try to modify the "soil" over time to help it support some sort of life.

Sigh.

Adam.

Adam, where on earth do you live in NYC that you have a garden plot? Surely not Manhattan? What my aunt and grandmother did, living on a barrier island with sandy soil, was to "double-dig." Everytime they planted, they dug off several inches of soil and placed it aside, then they dug deeper and placed it aside mixing compost into both piles. Then they put the FIRST pile into the bottom of the hole and the SECOND pile into the top of the hole. This second pile would eventually be as good as the first pile through the addition of mulches and fertilizers. They had beautiful gardens, but occasisionally a hurricane would wipe them out pretty badly. I saw the island, Wrightsville Beach, near Wilmington, NC, completely covered with salt water and ocean sand on many occaisions........but they persevered.

I live in the Riverdale area of the Bronx, in the northwestern~most corner of the city, a short walk from the shore of the Hudson River (a nice place).

My garden plot is a "community garden" on the property of a cooperative apartment building. After REALLY protracted negotiations with the Board of Directors (which imposed some interesting rules), I got permission to cultivate this section (which also has 500 sq feet of fertile south~facing border with unobstructed light).

In the section of the plot I am speaking of, construction for building repairs was staged (brick pointing, etc). Last season I removed nearly 3,000 pounds of debris, one bag at a time. By hand, alone.

In this area of the plot, there are several inches deep of mixed, crushed debris and dirt, and it's barren..., literally..., nothing grows.

I'm pretty new to gardening, but know a little chemistry, etc, so am hoping to get some basic ideas on a good course of action.

Thus, I really appreciate this sort of thread, as it helps me make the big decisions about "WHAT NEXT?"

Adam.

Despite all the soil science lectures suffered, what's left of my poor agric brain dribbles out my ears at the mention of cation exchange capacity.

Woodspirit has some great advice there, till/dig and add organic matter every autumn. Without knowing your specific situation (CEC omitted) I wouldn't like to comment much further. Many areas here that were bombed seemed barren but it didn't take too many years for plants to colonise, they live in all parts of the world on all sorts of soils, unless you live on soil like the Sahara sands, I suspect that plant life can and will be supported if the area is left be.

Of course, you want to make a garden so tilling, digging and adding organic matter is the best way to do this. In no time at all (well OK a few years, which to the world is just a blink fo an eye) you will have an area that supports a whole range of plants. If you can find any gardener who is completely happy with his soil and garden, you will have found a rare bird indeed.

Just followed this answer from Ulrich in the ID forum, alot of info here, haven't seen all.


http://www.scs.leeds.ac.uk/cgi-bin/pfaf/arr_html?Osmanthus+x+burkwoodii

Adam, before you start breaking shovel points on your soil, you might want to take a look at a book called Weedless Gardening by Lee Reich. "...a system of gardening from the top down that protects the soil, eliminates heavy work, and reduces water needs." He brings a great deal of thought, experience and knowledge in to bringing together all of the pieces of the puzzle. Dr Reich worked in soil and plant research for the USDA and at Cornell U. and advocated increasing the fertility of soil in the way that nature does it - from the top down. Just a thought.

To tag onto Kathleen's advice - it's really a pretty enjoyable read - not "cutsey" and not too dry and dull :)

The CEC ratio refers to the ability of the soil to release its nutrients. I haven't found any reliable numbers about a good range for it, but I do know that in a similar area of our yard, the CEC was 5.0. Nothing would grow there, either.

After a lot of work -- double-digging in literally tons of compost, the CEC was still low (about 10) but the other soil nutrients were somewhat back in balance, and now at least the horribly invasive groundcovers will survive. Turned out I had almost toxic levels of phosphorus -- 10 to 20 times the recommended maximum. No clue how that happened. I don't use commercial fertilizers. And the pH has dropped from 9.0 to 8.5 Still way too high, but that is the native soil -- clay limestone. Yuck.