I.D. This Weed Please

Enough of it will kill most blueberry plants.

Good ole Dr Reams again. Calcium Oxide is quick lime. It’s not an energy source for any plant. It will burn the roots of plants and kill blueberries in short order. Stay away from the stuff. It’s not intended for plants. Good for making cement not plants.

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Interesting you should say that. I’ve used limestone (Calcitic lime) a lot in my garden and my veggies look green with thick healthy stems and lots of volume of produce - just like they said would happen.
Of course blueberry plants love a more acidic soil, but I grow a bazillion other things which have responded well. So each of us have to find what works and which gurus have experience and know-how and which don’t. We all get to pick. :grin:
I love to experiment and put ideas to the test. For me that is the fun part of gardening.

Limestone is good for many plants in acidic soils. Quicklime is another matter all together.

Just to be clear, neither I nor the IAL folks were suggesting Quicklime. Did not mean to leave that impression. Calcium carbonate (hi calcitic limestone) is broken down in the soil to Calcium Oxide by microbial action. So limestone (recommended for soils) will be changed at some (likely very slow) rate to Quicklime, and the plants survive. :grin:

Only reduced sulfur compounds acidify. Calcium sulfate (CaSO4-2H2O, Gypsum) has oxidized sulfur bound to oxygen SO4(2-). Under the oxygenated conditions required for fruit trees to survive sulfate is stable.

Reduced sulfur compounds are elemental sulfur (yellow sulfur in the S(0) oxidation state), sulfides (bound with metals or as hydrogen sulfide), and most organic sulfur compounds (cysteine, glutathione). Bacteria naturally present in soil can oxidize sulfur and sulfides to sulfate, producing sulfuric acid in the process.

Ammonium (NH4+) acidifies because under oxidizing soil conditions, it is relatively quickly transformed to nitrate (NO3-) by soil bacteria. The H+ is released from the ammonium to the soil, acidifying it.

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The equation below says that carbonic acid as is present from dissolved CO2 in rain dissolves lime (calcite) to form bicarbonate and dissolved calcium.

CaCO3 + H2CO3 (carbonic acid) → Ca2+ + 2HCO3-

No CaO is formed under ambient conditions. In fact, with water and water vapor present CaO forms slaked lime which is Ca(OH)2. Over time slaked lime will take up carbon dioxide from the air to form calcium carbonate. This reaction is the reaction that takes place in the hardening of mortar.

Depending on the soil, Ca2+ can be taken up by clay minerals and organic matter. Calcium also helps clay particles stick together, and helps the structure of soil.

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Thanks much for the info! Chemistry was my weak point!

That is interesting as blueberries are low in nitrate reductase and often Ammonium sulfate is suggested, so I’m confused now?

Thanks Drew. May we cast the discussion in these terms (thanks to Rumsfeld):
There are ‘knowns’ (eg ions that react w/Ca, what ions need to be present for these reactions to even happen, what acids are excreted by plant roots to make minerals available); and then there are ‘known unknowns’ (whether we have acid rain, what ions are present (or not) in our soil to make these Ca reactions happen in the way you describe (or not), what microbes are in our soil to assist w/Ca and other mineral availability); AND most importantly the ‘unknown unknowns’ aka surprises. We can analyze this to death. Rather than dismiss it (people tend to be ‘down’ on what they are not ‘up’ on), I chose to experiment with it the last 2 years and have had very good results, which motivated me to look into it (I call it alternative agriculture).
Dr Beddoe in his book Nourishment Home Grown tried to explain you-know-who’s principles to the home gardener. Kinda technical but fun reading.

Anne, don’t get me wrong, the more help the better. Your info about weeds is extremely useful, and I didn’t know about that book which sounds very interesting. We need every tool we can get our hands on!
You mentioned acid rain. For the last three years I have tested my rainwater. I live 8 miles from Detroit. We make cars, our air used to be quite dirty, and yes acid rain was common. Well the last three years the rainwater has tested neutral. It’s never acid here anymore. Not one check ever showed the rain to be acidic. The equipment was calibrated correctly. Even natural rain should be slightly acidic from various chemical reactions that occur naturally, yet it is not? I can’t explain it?
My only thought is that local soil airborne from dryness is increasing pH when washed out in the rain. Also for sure the air, water, and land is a lot cleaner these days. Nice to see!

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I very much agree with you Anne. The most recent research in soil chemistry, microbiology, and plant interactions makes it clear that there is a lot we don’t know and it is truly “unknown unknowns”.

I also totally get the idea that natural “weeds” would tell you the state of your soil. It is why we have ecosystems like “mesic prairie” and “pine barrens” etc etc. If what you have going is working then that is great.

Knowing your soil is somewhere between science and deep soulful connection. :slight_smile:

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Drew -

That is interesting that blueberries don’t have much nitrate reductase. I should amend my statement on how rapidly ammonium is transformed to nitrate. It is on the scale of weeks to months, and that is determined, in part by soil temperature, moisture, how strongly the ammonium is bound to clays, etc.

So the suggestion makes sense. And has the added benefit of acidifying the soil to where blueberries want.

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Anhydrous ammonia is a very common fertilizer for field crops. When applied to warm soils the rule of thumb was it would take about one week to be converted to nitrate. My experience was the greening effect happened pretty fast in summer. Most field crops don’t efficiently take up the ammonium ion. It needs to be converted first. So I’d say it would only takes months in very cold, nearly frozen, soils. These are just my field observations not any controlled studies.

Thanks for elaborating on the chemistry. Makes more sense. I have been looking at some blueberry nutritional studies. Blueberries can absorb the ammonium ion fairly rapidly.
Interesting observation is this year I made a new blueberry bed an planted onions around it. I just had so many onion seedlings I grew from seed, I was looking for places to put them. Anyway they are growing way better than the rest! They either like the acidity, or the ammonium or both! Makes me think I need to acidify the beds where I grow onions.

I think the best way to kill purslane is to eat it. It tastes good and it’s high in omega 3/s.
JOhn S
PDX OR

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I grow a cultivated variety (a food forest item under some fruit trees) that serves as a Summer green. Purslane is one of the few plant based sources of omega-3. Here it is with some ‘Momotaro’ toms and a persian cuke. Note how large the purslane leaves are and the seed/flower clusters compared to the weed/wild variety:

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‘creepy’ spurges grow in the mojave too, but not invasive enough for locals to dislike them.

could be too hot and dry it does not have the chance to get weedy. Actually find it ornamental in a micro-kind of way. Here’s our flora and faux-na diorama.

and if you can’t beat it, have something eat it :grin:
it is supposedly a natural forage fare for desert torts
https://www.youtube.com/watch?v=2qaccTKTOA4&feature=youtu.be

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I’m late to this conversation and came upon it via a search for purslane. I saw some videos touting the high health benefits from eating purslane. I’ve found what I think is purslane in my yard but after seeing this thread I’m wondering if it could be spurge. They look very similar to me. Whats the easiest way to identify them? What about taste. If I pull a leaf off on it and taste it how do the two differ?

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Purslane has a lemony taste and succulent, edible stems. You can not die from trying a leaf.

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Purslane leaves and stems are thick and fleshy, like a succulent. Spurge is thin and wiry, and lays flatter. Don’t eat it if you aren’t sure!
If you are really interested in edible plants, I recommend John Kallas’s Edible Wild Plants for a great description of purslane.
In the meantime, can you post a picture of your plant. Preferably nice and close, like in the palm of your hand?

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