[HN Gopher] What elements does a plant need to grow?
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What elements does a plant need to grow?
Author : lathyrus_long
Score : 194 points
Date : 2021-11-16 16:12 UTC (6 hours ago)
(HTM) web link (github.com)
(TXT) w3m dump (github.com)
| GhettoComputers wrote:
| Great post! This reminds me a lot of making dog food for people
| (aka Soylent) with the best profile, requirements, and because
| plants don't complain about taste, you'll have no problem with
| ratios!
|
| The only issue is about the effects of these elements and what
| they can do to the water or your home. Would they need a special
| environment to prevent fungi, algae, bacteria or mold that would
| also feast upon these nutrients? You said bacteria didn't always
| appear but what if some will grow on hydro? What optimizations
| would you do for preventing infections?
| lathyrus_long wrote:
| Some growers keep their reservoir and root zone as sterile as
| possible, using additives like hydrogen peroxide or calcium
| hypochlorite. Others dose beneficial bacteria intended to
| outcompete bad stuff, like Bacillus amyloliquefaciens
| (Hydroguard, Southern Ag Garden Friendly Fungicide).
|
| Algae can use the same nutrients as the plants, but can often
| be controlled by excluding light. Other bad microbes are
| generally heterotrophs, so they're feeding on something else
| (like dead algae or dead roots).
| GhettoComputers wrote:
| Is it possible to make an ecosystem that is beneficial, like
| kombucha in a way? Will they be using indoor lighting like
| from weed grow LEDs (red and blue) or you planning all/mostly
| natural lighting? This is a really cool project, do you have
| any plans with plant hormones? I only know I used rooting
| powder, this article is interesting! I used ethylene as well
| to ripen foods with bananas but I didn't actually use them on
| my plants. https://untamedscience.com/biology/plants/plant-
| growth-hormo...
| julienfr112 wrote:
| Does someone have a system with arduino and concentration probe
| that match every nutriment individualy with it's exact optimal
| concentration ?
| flyingfences wrote:
| I've looked into exactly that sort of setup for a previous job
| a few years ago and the problem is that these probes don't
| exist for every nutrient and the ones that do exist tend to be
| very expensive. It wouldn't be a cost-effective apparatus
| unless it was set up with one probe station metering the
| outflow to the whole of an industrial-scale greenhouse.
| belval wrote:
| You know how sometimes you think about something and it appears
| out of nowhere the very next day? That's what this article is for
| me. I have been growing mint, basil, purple basil and rosemary in
| a custom NFT system for the last 5 months and I am starting to
| run low on my General Hydroponics nutrients which are somewhat
| expensive at ~100$ for the 3 solutions.
|
| This is very useful and I want to say a big thank you to the
| author for doing so much of the work I was planning to do!
| polishdude20 wrote:
| When you said NFT I got triggered. Then I realized this can't
| surely be the NFT I'm thinking about haha.
| belval wrote:
| My bad, should've known better than to use NFT on HN.
|
| For those wondering, it stands for "Nutrient Film Technique"
| and it's basically running a small stream of nutrient
| solution in PVC tubes with your plants' roots being somewhat
| submerged.
|
| It's a pretty water-efficient technique, this link explains
| it well: https://www.trees.com/gardening-and-
| landscaping/nutrient-fil...
| cwkoss wrote:
| Have you considered selling your Nutrient Film Technique on
| the blockchain?
| stevespang wrote:
| professional degreed horticulturist here:
|
| 1) grinding your own ferts is nonsense, JR Peters makes the best,
| hands down.
|
| 2) I built my own RO system with permeate pump years ago for like
| $350 in parts off the internet, uses pressure bladder tank and
| solenoid on timer (dumps every 45 min or so) to fill a 55 gallon
| barrel every 24 hours. I use the largest ice maker
| hexametaphosphate cartridge filters to control the calcium and
| keep it soluble so it will not poison the RO membranes,I get
| about 20 days on each hexmetaphosphate filter cartridge.
|
| Ph control is done with sulfuric acid from Duda Diesel, 1/2
| capful in 55 gallons of plain city water (not needed for RO
| water) - - comes out to about 6.5 after 24 hours. My water is in
| limestone country, about 450 ppm soluble salts.
|
| Duda used to sell the real deal,it was syrup like and super
| dangerous, now it's watered down crap, still it will burn you
| real fast. Always wear gloves, full face mask and apron. You can
| also use weak battery acid from auto parts store, weaker.
|
| Many orchid growers use more expensive citric acid, they keep it
| mixed in concentrate tank for days,they are not loosing it's
| strength in hours as you suggest.
| serverholic wrote:
| Question: How do we know that we are giving plants everything
| "we" need?
|
| We get nutrition through the food we eat and there are many, many
| molecules that contribute to our health. This project is cool but
| I worry about subtle nutritional deficiencies if this food ends
| up being the majority of a diet.
|
| I have the same worry when it comes to lab-grown meat.
| outworlder wrote:
| Where would the plants store useless (to them) elements and for
| what purpose?
| Djrhfbfnsks wrote:
| I don't know the biology, so I can't answer specifically, but
| surely there are many cases of "useless" and even detrimental
| elements being stored in living bodies. Just look at heavy
| metal accumulation in animals for example.
| comrh wrote:
| Really nice documentation, well done.
| lathyrus_long wrote:
| I've been growing hydroponically through the pandemic. I'm now
| switching from commercial pre-blended nutrients to my own design,
| customized for my hard water and blended from individual salts.
| In the linked article, I briefly review the biochemistry, show
| the fertilizer design calculations using an open-source tool that
| I wrote, and review a lab analysis of the final solution.
|
| This is a fair amount of work, and I'd guess that relatively few
| non-professional growers would bother. I hope this may be
| interesting to anyone generally curious about plant nutrition
| though, or about the design of modern complete chemical
| fertilizers.
| holonomically wrote:
| Very cool. Thanks for putting this together.
| drewnoakes wrote:
| I'm curious to know how stable the blend of elements in tap
| water is. Do you have any data around this?
|
| I once used an inexpensive electrical TDS meter (total
| dissolved solids) to track the amount of non-organic solids in
| water both before and after filtering over time. My goal was to
| determine the rate at which to replace the filter, and it
| turned out the manufacturer's recommendation was perfect.
| However I did notice that the unfiltered water's measurement
| fluctuated a lot over time. Could that pose a challenge in your
| scenario?
|
| Thanks for a great read, btw.
| lathyrus_long wrote:
| I have a drain-to-waste system running open loop, with a
| constant dose of acid and sensors monitoring the pH of the
| leachate that drains from the pots. In that system, I've seen
| step changes in that pH that I believe correspond to step
| changes in my source water, perhaps when my utility changes
| which wells supply me. Hard to say without a detailed water
| analysis, but I'd guess the changes in nutrient profile
| (e.g., ppm Ca) aren't too important, and that as long as I
| adjust the acid dosing to maintain target pH the plants won't
| be affected much.
|
| A single well may also show gradual seasonality, like from
| snowmelt and such. I assume that's happening too, but in my
| current setup that would be hard to distinguish from gradual
| pH variation due to changes in the plant nutrient uptake.
| chana_masala wrote:
| Wow, do you have more resources for the drain to waste
| system?
| belval wrote:
| Impressive work! I had a couple of questions.
|
| - How do you find the best concentration for each nutrients for
| a given plant? I usually just make general-purpose mix with
| General Hydro but I see that your calculator includes some
| presets for specific plants.
|
| - I see that your board includes pH and EC probes. I always
| wanted those in my setup but I've read that they tend to
| degrade fast. In your experience is that true?
|
| - Where did you get the potassium nitrate? I always wanted to
| make my own mix but I've heard that buying large amounts online
| will put you on a list as it's a strong oxidizer (you can make
| explosives with it).
| 34679 wrote:
| Not OP, but I can give an answer to the first question.
|
| It starts with simply observing the plants. You can vary the
| dosage from crop to crop or between plants in the same crop.
| Plants with leaf tip burn will generally have too high of a
| concentration and plants with pale leaves will generally not
| have enough nutrients. This assumes other factors like pH are
| correct.
|
| Another option is leaf/flower/fruit analysis. For example, if
| you're growing spinach, you may view iron content as an
| indicator of quality, healthy plants. Determining the iron
| content of the leaves from plants dosed at different rates
| will help zero in on the optimum fertilizer program.
|
| The best way, IMO, is to test the nutrient solution before
| and after it has been "fed" to the plants. This requires a
| recirculating system for best accuracy, but runoff can also
| be collected in a drain to waist system. As the author
| mentioned, unused nutrients will build up in the solution. An
| ideal solution will have the nutrients used by the plants at
| the same ratio they are found in the virgin solution. Any
| skew from that over time will indicate which concentrations
| should be adjusted and by how much. It can be a tricky beast,
| however, as the uptake rate of any individual nutrient is
| influenced by the presence of other nutrients. Change one and
| you may create an imbalance elsewhere. Like most things, it's
| a process.
| belval wrote:
| That last part is interesting to me, how would you test the
| nutrient solution after circulating? Would you just pay a
| lab to run the analysis on what's left or evaporate the
| solution to increase concentration and then try to
| precipitate the ions left in the solution and weight those?
| lathyrus_long wrote:
| You'd pay a lab about $45, same as I did for my quality
| control check. A few of the ions--like nitrate or
| ammonium--will probably get tested with some kind of
| color-change reaction, and quantified with a visible-
| light spectrophotometer. The rest will be from ICP
| (inductively coupled plasma), a precisely-quantified
| version of the same effect as where different elements
| make a flame turn different colors.
| lathyrus_long wrote:
| The nutrient profiles in my calculator are copied from
| various academic publications. Those profiles typically come
| with less discussion of how they were designed than I might
| hope, but I assume it's from review of trials of the form
| mentioned in the other reply to your comment. For more
| profiles, I've never used anything from
|
| https://cdnmedia.eurofins.com/corporate-
| eurofins/media/12142...
|
| but I suspect from the author's bio that it's trustworthy.
|
| For probes, see
|
| https://github.com/hydromisc/hydromisc/blob/master/doc/senso.
| ..
|
| EC probes should last basically forever if correctly excited
| (zero net DC). pH probes are consumables, but my $10 probe is
| still happy after a year continuously immersed. As process
| fluids go, hydroponic solution is pretty mild, neutral-ish pH
| and decent ionic content.
|
| I bought the potassium nitrate from MBFerts in combination
| with other fertilizer salts, so if I'm on a list it's
| probably "cannabis growers" and not "mad bombers". If you'd
| rather not use it, then a quick experiment in the calculator
| shows you can still hit a decent profile with just calcium
| and magnesium nitrates.
| belval wrote:
| Very interesting, thanks!
| indiv0 wrote:
| If you got a reverse osmosis filter and thereby worked with
| neutral water as a starting point, would it be easier to
| achieve your target ratios? You wouldn't have to account for
| existing concentrations in the tap water.
|
| Also, I was under the impression that there are two stages for
| plant growth: vegetation and fruiting. The two stages have
| different requirements for nutrients:
|
| - high nitrogen, mid phosphorus, low potassium; and - low
| nitrogen, mid-high phosphorus, super high potassium
|
| respectively. Do you use the same mixture for both stages?
| dkarp wrote:
| Very cool. Do you have any pictures of the full hydroponic
| setup (with plants)?
| lathyrus_long wrote:
| There's one in my post about the automation system, at:
|
| https://old.reddit.com/r/Hydroponics/comments/o8j68n/singleb.
| ..
|
| That was still with the old commercially-blended nutrients,
| though. I've so far used my custom blend only for a few bok
| choy, as a final quality control check since they're fast-
| growing. If those continue to look good, then I'll move my
| entire balcony to the custom blend in about a month.
| dkarp wrote:
| The tomato plant is huge! It seems quite foliage heavy
| though, do you think that's because of the commercial
| nutrient blend you used? Have you also looked at modifying
| the recipe at different stages i.e. during growth,
| flowering, ripening?
|
| What climate zone are you in (if you don't mind me asking)?
|
| I'll be growing a bunch of things in Spring and would like
| to make a setup like this. I'll keep an eye on the project
| and likely contribute if you're open to it
| lathyrus_long wrote:
| > It seems quite foliage heavy though, do you think
| that's because of the commercial nutrient blend you used?
|
| Mostly inadequate pruning, I think--I was planning to
| replace it soon, so I'd gotten lazy. Normally I remove
| side shoots and lower leaves, for less foliage and better
| yield. The fertilizer was Masterblend 4-18-38, which is
| intended for tomatoes and pretty close to the University
| of Florida's "Stage 5" tomato profile (per their article
| linked from my calculator). So I'd guess the nutrient
| profile was close to optimal, except for all the excess
| phosphate from my pH down.
|
| I'm on a somewhat protected balcony in San Jose, USDA
| Zone 9B. That's warm enough that I can grow tomatoes
| through the whole winter, as long as it's a cold-tolerant
| cultivar (e.g. Early Girl; or Sub-Arctic Plenty, which is
| a determinate so needs less/no pruning), and lots of
| other stuff too.
|
| And contributions definitely welcomed, especially on the
| controller firmware. That's currently in a state that's
| useful only to programmers. More work there (integration
| with home automation software, a nice browser-based
| interface to schedule irrigation and dosing, etc.) would
| make that accessible to a lot more people.
| jcims wrote:
| Regarding the automation, I built a DIY closed loop
| distillation process with similar i/o requirements. I have
| nowhere near the skill required to build a dedicated board
| but found that node-red running on raspberry pi using mqtt
| to talk to nodemcu running tasmota created an extremely
| extensible and modular platform. I'm running 8
| thermocouples, two pumps, two flow meters, two load cells,
| current sensing coil and zero crossing ssr to chop current
| to a 6kw 240v heating element. With tasmota the little mcus
| are just kind of like legos and i just put them where the
| wiring is convenient and keep some spares.
|
| All of the i/o is dumb, the control loops are all on the
| node-red flowgraph allowing for lots of visibility of terms
| when tuning pids.
|
| The node-red dashboard lets you mix telemetry and control
| on a very touch friendly format, and i spool all of it to
| influxdb to compare runs over time.
|
| I'm sure you've got what you need with what you've built
| but at a minimum node-red might be worth a look. I was
| suuuper impressed using it for this.
| uhhyeahdude wrote:
| That seems like a perfect use of node-red. Your setup
| sounds pragmatic and effective; I'm sure there would be
| an audience for some kind of write up with diagrams,
| especially if it also functions as a node-red tutorial
| (of sorts). I know that I am regularly designing control
| systems for hobbyist ag setups, and I pretty quickly hit
| a wall due to having minimal coding background. Something
| like node-red seems really useful for someone in my
| situation. Thanks for the ideas!
| itsgrimetime wrote:
| also interested in seeing pictures/diagrams of the setup
| noud wrote:
| Very cool project!
|
| Do you know if there are any benefits of growing hydroponically
| compared to the conventional (farming) methods? Is it
| economically interesting? Is it more sustainable?
| smileysteve wrote:
| Uses 5% of the water (few losses to evaporation)
|
| Time to harvest is typically 2-3x less / faster.
|
| Yields are 2-3x in volume (targeted nutrients, more hours of
| "sun")
|
| Can grow small without a yard (ie Condo, Apartment,
| Townhouse)
|
| (https://www.trees.com/gardening-and-
| landscaping/advantages-d...)
| smileysteve wrote:
| Much less interesting than this formula, but I grow with an
| Aerogarden.
|
| Takes ~2 weeks to 1st Harvest, lives on a bookshelf in my
| living room, 6 plants produce a salad for 2 about 1x a
| week. Lettuce is flavorful. I expect a single "planting" to
| last about 4 months (having done this a few times)
|
| In comparison to my outdoor winter crops (including Kale
| and Broccoli) , all planted around October 7th; Outdoor
| Kale and Broccoli aren't to first Harvest yet (estimated
| ~60 days)
| kortex wrote:
| > Sulfuric acid or nitric acid would have a more favorable effect
| on the nutrient profile, but they're more and much more dangerous
| respectively.
|
| Sulfuric acid is not really that dangerous unless you are getting
| the high test stuff from a chemical supplier. You can use battery
| acid refill solution, it's just deionized water and H2SO4 at
| around 30% concentration. That's mild enough that it won't cause
| any immediate burns, but you should still wear gloves and goggles
| when handling it.
|
| There's no need for nitric acid, since you are already supplying
| nitrate ions.
| lathyrus_long wrote:
| Yeah, battery acid is sometimes used, and not a terrible
| corrosive risk with the precautions you note. I don't love that
| it doesn't come with any specs e.g. on heavy metal
| contaminants, but I think it's near-certainly fine in practice.
| ACS grade would have specs, but I don't want to handle the
| concentrated acid.
|
| Sulfuric acid would give me excess sulfate, but since the
| plants aren't too sensitive to that I expect that would be an
| improvement over my current excess phosphate. I'm not sure if
| I'd get calcium sulfate precipitation as the reservoir
| concentrated. Nitric acid would let me hit my target profile
| exactly (with a corresponding decrease in nitrate salts), but
| it's way more dangerous. I've seen nitric acid used in academic
| trials and in countries with weaker safety laws, but not
| commercially in the USA.
| [deleted]
| beebeepka wrote:
| This reminds me.
|
| In my layman's mind, having agriculture right next to roads is
| bad because vehicles are dirty.
|
| Recently, someone told that's not the case because "plants need
| this stuff". Any truth to that claim? I'm yet to read the article
| intrasight wrote:
| Plants for sure absorb things they don't need, and that are
| toxic to themselves and to us.
| boldslogan wrote:
| My childhood experiment actually comes in handy! I can confirm
| at the least that planting half of the same batch of seeds
| close to a road's (the tarmac's) edge next to it, and in a
| forest, my grass seeds grew much worse next to the road.
|
| Also I was told to never eat berries growing from a bush close
| to a road since they are more dirty.
| spaetzleesser wrote:
| Brawndo has what plants crave. It's got electrolytes
|
| Idiocracy
| outworlder wrote:
| They weren't even wrong.
|
| I would totally buy a Brawndo hydroponic formulation.
| dangerboysteve wrote:
| This was the very thing thing which came to mind when I read
| the title.
| [deleted]
| 71a54xd wrote:
| Soilless media (commonly used for growing marijuana) was actually
| a game changer in my apt for indoor plants during the pandemic.
| If you have any issues with fungus, gnats or any kind of negative
| root insects soilless media is the way to go. Fertilizers that
| incorporate beneficial endophytes are also fascinating. However,
| steer clear of nutrient blends like Noot though - they're watered
| down and urea derived which is a great way to stress and kill
| your house plants.
| lathyrus_long wrote:
| > If you have any issues with fungus, gnats or any kind of
| negative root insects soilless media is the way to go.
|
| Yeah, though with the caveat that if your medium retains water
| very effectively (as e.g. rockwool does) and is exposed to
| light, then it may grow algae. The larvae then feed on that
| algae, and the problem is back.
|
| I spend a lot of time fighting fungus gnats. The best option is
| always to adjust growing conditions to create an inhospitable
| environment for them, but I also make recourse to Bti (a
| bacterial toxin, like mosquito dunks) or pyrethrin sometimes.
| DaftDank wrote:
| It takes a lot of patience, and good IPM, but living soil has
| been awesome to me. We often say we grow soil, rather than
| plants, because of the fact a healthy living soil will provide
| all the nutrients the plant needs, and all you have to do is
| water essentially. Speaking strictly from a marijuana perspective
| (the limit of my experience with living soil), it makes the
| marijuana taste better and have a better smell. I've seen two
| different growers, starting with the same clones from the same
| mother planet, where one grows in soil using bottled nutes, and
| the other does living soil. The living soil definitely was
| superior.
|
| With that said, living soil is not practical for everyone. Trying
| to do it indoors where you also live could create issues if you
| do not have a good IPM strategy, and fully understand the soil
| food web. "Teaming with Microbes" by Jeff Lowenfels is an
| _excellent_ book to learn about how the soil food web works.
| wefarrell wrote:
| So long growers are maximizing THC content and yield per area
| Hyrdo will outcompete organic soil. Personally I grow organic
| because I too prefer the taste and I really enjoy composting.
| However having grown in hydro I can tell you that plants grow
| bigger, faster, and more potent.
| dr-detroit wrote:
| By soil you mean cocoa right?
| sampo wrote:
| IPM = Integrated Pest Management
| Baeocystin wrote:
| What do you do about spider mites?
| bastardoperator wrote:
| Outside of light, nitrogen (N), phosphorus (P), and potassium
| (K), or NPK for short
|
| Finding the right combination of these elements is what
| hydroponics farmers do everyday, pushing the limits of their crop
| for maximum quality/yield. We are starting to see a big shift in
| hydroponic fertilizers from liquid to powder since nobody wants
| to pay for shipping water.
|
| I highly recommend https://github.com/kizniche/Mycodo for anyone
| doing anything in hydroponics.
| zuminator wrote:
| The article lists 16 required elements: C, H, O, N, P, K, Ca,
| Mg, S, Fe, Cu, Mn, Zn, B, Mo, Cl.
| amelius wrote:
| In what forms?
| onecommentman wrote:
| As do most other websites like
|
| https://agrilifeextension.tamu.edu/library/gardening/essenti.
| ..
|
| Interestingly none of the critical semiconductor elements are
| required by plants: Silicon, Germanium, Gallium, Tin, Gold,
| Silver...
| Radim wrote:
| _> Outside of light, nitrogen (N), phosphorus (P), and
| potassium (K), or NPK for short_
|
| Ehm. Check out this Nature article on the importance of Carbon:
|
| https://www.nature.com/scitable/knowledge/library/effects-of...
|
| Very readable and worth reading in full. Especially the effects
| of elevated CO2 on the C3/C4 photosynthetic pathway and crop
| yields.
| bshipp wrote:
| Hydroponic growers are intimately aware of the need and
| benefits accruing from elevated CO2. You'd be hard pressed to
| find a greenhouse vegetable farm without a huge CO2 tank
| outside, as well as the technology used inside the scrub
| carbon dioxide from natural gas exhaust and reroute it into
| the plants. They tend to burn the natural gas during the day
| to feed the plants while storing the heat in huge water tanks
| to warm facilities at night.
|
| The primary constraint is maintaining low enough CO2 levels
| to remain healthy for the humans that work inside the
| greenhouse. Plants themselves can handle very high levels of
| carbon dioxide.
| chilling wrote:
| Nice work. I really admire your hardware setup. However it's
| worth adding that most of blooming plants will change their
| 'diet' during their flowering period. Some will continue to grow
| through the whole cycle on one mix and other (like tomato,
| cannabis) need some additional nutrients dj'ing. I've been
| growing succesfully 'passiflora edulis' in hydroponic setup for 3
| years (continuously) and still I'm using hydroponic as a great
| kindergarden for most of my new plants.
| lathyrus_long wrote:
| > However it's worth adding that most of blooming plants will
| change their 'diet' during their flowering period.
|
| Yeah, absolutely. I tend to grow a lot of different plants at
| different life stages, so an optimal profile for each one would
| be a lot of work. I'm certainly paying a cost in yield for my
| laziness, though.
|
| At some point I should redesign my nutrients into three parts.
| I've got support for a fourth dosing channel (fertilizer A,
| fertilizer B, pH, spare) in my electronics, so it's just
| another pump and the plumbing.
| jazzyjackson wrote:
| I came by a book on "micro-propagation" once (getting diced up
| plant samples to root in a petri dish) - it discussed the old
| fashioned way to propagate orchids (once you have a mutation you
| like, you have to clone that one plant by however many you want
| to sell) - apparently coconut water was used as a nutrient
| medium.
|
| Found a source that discusses its use [0], apparently is has
| beneficial hormones as well, "Besides its nutritional role,
| coconut water also appears to have growth regulatory properties,
| e.g., cytokinin-type activity"
|
| [0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6255029/
| intrasight wrote:
| It's "what molecules" a better phrasing?
| lathyrus_long wrote:
| "What ions", strictly--they're salts, so they dissociate when
| they dissolve. But it's conventional to look at the breakdown
| by element, not by ion, even in cases where the specific ion is
| important. For example, fertilizers give "percent nitrogen from
| nitrate" and "percent nitrogen from ammonium", not "percent
| nitrate" or "percent ammonium".
| adriand wrote:
| What's insane to me is how much certain plants will grow in tap
| water with zero regard for their nutritional requirements. I
| frequently propagate houseplants by putting cuttings in a glass
| of water and sometimes I get lazy and don't re-pot them for weeks
| or even months. And they will often grow very well - shooting out
| tons of roots but also additional leaves and stems.
| BurningFrog wrote:
| I believe it takes most of the material for air, not water.
| soperj wrote:
| Bottoms of green onions to me are the weirdest. You can get
| multiple cuttings just from water.
| 71a54xd wrote:
| Hard water is actually one of the worst things you can give
| to expensive house plants, distilled water is by far the best
| option to prevent root calcification and ph swings.
| lathyrus_long wrote:
| You can also acidify the water down to a reasonable pH,
| though even phosphoric acid is somewhat dangerous and the
| best choices (nitric or sulfuric) aren't something I want
| in my apartment.
|
| Amateur hydroponic growers often use reverse osmosis water,
| somewhat wasteful but cheaper than distilled. You can get
| RO systems designed for aquarium use with no pressure tank
| at the output and just let them slowly fill a barrel or
| tote, over hours or days.
| soperj wrote:
| Don't know why I got this reply? Green onion bottoms that
| normally would go into the compost aren't expensive, and
| the tap water here is very soft.
| GordonS wrote:
| What about tap water from countries where the water is
| soft, like Scotland, Ireland or Norway? Or is that still
| too "hard" for plants?
| lathyrus_long wrote:
| I think that's not by accident. Typical houseplant species seem
| to be selected for their ability to look good with minimal
| fertility. That makes them easier to grow, but harder to grow
| optimally. For example, mint will quickly indicate any
| deficiency in its leaf appearance, but pothos / devil's ivy
| will mostly just grow slower.
| GhettoComputers wrote:
| That's the same as saying there are animals that have more
| biological fitness (mice) than others (pandas). Carbon and
| nitrogen come from the air, water will hydrate them, but most
| plants have expectations.
|
| Orchids for instance can be artificially bloomed with
| phosphorus but if it was dormant people would just think it's
| dying, as if natural cycles of less bloom was a failure of the
| plant's growth!
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