Trichs & Gypsum? Lime? Avoiding Stretch When Rooting Cuts?

[Derkshaman]

Howdy everybody. I just wanted to discuss a couple simple things that I've been wondering about for a very long time- would appreciate input. This thread isn't very specific but assume the discussion still holds some value? I'm fairly new to these forums and hoping that it's appropriate, and not beating around the bush.... So:

Firstly. Does anybody use gypsum for their trichocereus? It's cheap, and provides extra calcium and sulfur. I understand that it's especially beneficial for plants in heavy clay, which is abundant where I live- it supposedly helps water & roots penetrate. What I'm unsure of is if whether it holds any benefit to trichocereus, and if it actually sticks around in soil (it appears to wash right through). Can any experienced growers tell of their general opinion with Gypsum? And more specifically, is anyone aware how the mineral effects soil PH?

I used to, and still do use some dolomite lime: from what I understand it buffers soil to the neutral PH of 7, which is ideal many plants including trichocereus. But shortly after my last application I noticed that the growth tips turned oddly pale, and began to lack vibrancy. After a little more research, I discovered that dolomite lime has an excessive magnesium:calcium ratio for most soils: would this likely be responsible for the shift to pale yellowing on growth tips? Also, shortly after applying gypsum (which in theory would shift the ratio back to a higher calcium:mag) the vibrancy appeared to come back.

Secondly- a problem that I often experience when rooting cutting is etoliation, or rather thinning of the growth tip. Is there anything that can be done to avoid this issue, or has anyone noticed any correlations? Sometimes cuttings keep growing without ever getting thinner, and sometimes they get incredibly thin with a long time before beginning to grow more widely. I assume more light would help, but in my experience this hasn't seemed to do much in preventing the issue... not to mention shade is necessary as to not fry the unrooted cuts.

[Conv3rgence]

My cuts get full sun from dawn till 11:30am then full shade. No etoliation, actively growing even before rooting.

[BedOSpines]

You should throw away dolomite lime, unless your sure you need magniesium, which is doubtfull. Ive had good results with calcium carbonate, gypsum and soft rock phosphate. Are they growing indoors?

[Sallubrious]

So have you done any soil tests or are you just randomly adding things to the soil ?

Gypsum is good for some soils but can also be toxic in others. The clay breaker aspect of it is greatly overstated as it will only loosen some soils. If you have a sodic soil with low levels of calcium it can help, but most of the time it's not needed.

As bed of spines said dolomite can cause problems too and in some soils it can lock up the available calcium and cause deficiencies.

Get a soil test before you start messing with the soil chemistry.

[endorfinder]

I second Sally especially on the clay breaking - I've never found it useful in this regard period, even though that's often what its principally marketed for.

Great for mushroom grain spawn though..

[Derkshaman]

Ahh, thanks for the advice guys, it's quite valuable.

I grow outdoors in a lot of heat and sun.

The reason that I bother using Lime actually isn't just for the hell of it- I often use different types of organic fertilizers which I know tend to make the soils go acidic, especially alfalfa meal. Although I haven't bothered doing soil analysis, I assumed lime to be more harmless (with a buffering, neutral PH) than it now appears to be, so I would add it periodically in an effort to stabilize the pH. I now understand that it actually has very limited use?

I definitely ought to be using another form of calcium for my pH needs. Dolomite lime was just so appealing to me due to the perceived forgiving-ness of it's neutral pH buffering characteristics. I hadn't understood until recently the concept of calcium:magnesium balance.

Additionally, I didn't understand that Coco Coir had a neutral pH, and is most effective when maintained at a pH of around 6. I misinterpreted this as coir being at a pH of around 6, therefore benefiting some buffering towards a pH of 7. In reality this seems to be terrible for plants- luckily I didn't start using coir until recently and have only managed to hurt a few seedlings.

The gypsum, on the other hand seems more to be 'for the hell of it'. All of the fertilizers that I use appear to lack sulfur, and with my understanding of gypsum's effect on soil pH (or lack of), it seems like a safe way to obtain sulfur.

I'm beginning to think that I'm making things too complicated- just always striving for maximum growth and health. I'll probably go back to using just good soil, with occasional soluble ferts like I did in the past years. The leaves are soon to fall- almost time to compost again.

Edited November 13, 2015 by Derkshaman

[BedOSpines]

Not very recent imo lol, you should look into Dr William Albrecht's work. but currently I think the high N ferts, and pesticide industry are making more profit lol. Is it the Brunnings coir? mostly i find they have time release ferts added. I've been using coir with great success (not Brunnings) . after you read some of his work you tend to stop caring about ph so much, just make the soil properly and it will self regulate. and usually coir is super high in sodium as its mostly grown near the ocean and washed in ocean water over in India, pays to wash it, super pain tho lol. certainly coir is calcium deficient though as is every other bagged product i seem to come across x.x

[Derkshaman]

I actually just use some straight up multi purpose compressed coco coir. It's marketed for reptile & amphibian enclosures so it comes pretty clean. I washed it well anyways, and... well, I tasted a little bit to make sure it wasn't in the least bit salty.

Is coco coir really worth the trouble for growing cacti? Is gypsum or dolomite lime useful at all in this substrate? If I understand correctly, coir only functions well below a pH of 6.5- since the local dirt, my current compost, and the bagged soil that I use is all at a pH of around 7, it probably is detrimental to mix any coir in, correct?

I'd like to learn how to make my own mixes using peat. It just seems a little complicated. I've only ever made mixes with compost, dirt, sand and pumice.

[Conv3rgence]

I dont like peat because of how it goes all hard and water repellant when it dries out. With cacti and succulents you regularly dry out the mix before rewetting, so peat just goes to shit. Peat only seems good if it can be constatntly moist. This is why people like coco coir, because it dries out and rewets just fine.

Honestly, for trichs, you should be fine with your list of compost, dirt, course sand and pumice. You could try adding washed nutrient free coir instead of some of the dirt, but what you have there sounds fine to me.

[pinegapcontrol]

i have heavy clay, to the point where i cant plant out where i am, almost everything i have is in pots. less than a foot down, depending on the seasons, it is either slop or solid clay like you would get from an art shop. i have a few testers in ground that was heavily covered in gypsum 6 months before planting, the majority of what ive planted is growing very slowly and turning yellow.

after reading that stone eaters article i have gone off anything lime/calcium related. it suggests its a growth inhibitor. but it depends what you want i guess, a lot of them have lime/calcium in their natural environments.

[endorfinder]

If you want to adjust pH then dusting sulphur isn't a bad option, not too brutal. My understanding is that it is slowly converted by soil microbes into sulfuric acid over the course of a couple of weeks. Meters are cheap and much easier to use than those silly test kits. There's a lot of cheap gardening stuff on AliExpress if you're happy to wait a couple of weeks for delivery from Asia.

You can also just piss in your pots to good effect.

Plants that truly care about soil pH are pretty few and far between though.