Comment by kodah | Hacker News Reader

Comment by kodah | Hacker News Reader

Caring for houseplants is quite hard. I have 8 and my friend recently gave up his job to grow Bonsai trees full time. The amount I learned from him was quite interesting, I almost felt dumb by the end. My plants do fine, but they could've been doing way better.

For my Bonsais, I didn't know that they should be given filtered water. The Bay area has particularly nasty water, so immediately my plants were getting spots. Second, when you repot in the summers, the soil should be aligned to where you're growing. Third, East facing windows that cliff the sun at the hottest part of the day are imperative. I then asked him, "Wait, I can't leave them in the same spot all year?" and his immediate reply was, "Hell no, not unless you plan to layer shades in front of them, but I bet that's not why you put them where you did." For watering guidance, he said, "Stick your finger into the soil down to the knuckle, if it's dry, water them. If it's still wet, let it dry out."

Keeping plants alive is relatively easy; helping them thrive is another matter entirely.

Trees and plants in the wild are watered by rain. Don't use the stuff out of your tap/faucet. Chlorine is great for killing off bacteria in stagnant water in pipes and so on but not so good for your plants. They don't care about Legionnaires etc that kills us lot off. Your plants want the raw stuff out of the sky so get a water butt and feed it from your house roof.

In the wild, plants are not surrounded by walls, floors and ceilings. They are, however, surrounded by other plants and trees that are trying to out compete them for the basics - water and sunlight.

Indoors the basics are: Water: rainwater only, unless it runs out then tap for a few days at most. Moist but not wet. Light: Some but not direct all day.

Now, some plants prefer more or less eg a Venus fly trap prefers constantly wet roots and direct hard sunshine. A orchid might like 7-14 days of drought and then a good dampening for a day or so (never static water).

It really isn't rocket science. You just have to remember that plants never evolved to live inside houses. Your mate that said "For watering guidance ..." is spot on. Just make it rain water and not tap if you can.

I had such a big problem using tap water on peppers and marijuana. Turned out it was to basic and the water was causing them to slowly die. I had to treat my water to fix the pH every time I watered. Such a hassle.

I take it you mean alkali.

My best tip on looking after plants is use rain water. Oh and actually water them and don't drown them unless they are swamp or bog plants.

No need for rainwater; chlorine evaporates, so leaving a bucket of tap water overnight will dechlorinate it naturally. Some particularly fussy plants do require extra filtered water, though.

Chlorine yes, Chloramine no. You need to know what your water utility is using, and be aware that it can change from time to time. Sometimes they'll use Chlorine most of the time, but periodically use Chloramine to address parts of the network that may not get sufficient Chlorine treatment.

Sodium Metabisulfite (Campden) will reliably remove either, as will reverse osmosis.

> the soil should be aligned to where you're growing.

What does it mean to align soil?

>The Bay area has particularly nasty water

Isn't Hetch Hetchy water some of the cleanest?

Yes it is and it's perfectly fine for house plants. TDS (total dissolved solids) is usually below 30 PPM, at least for me. But, there are parts of the Bay Area with less pure water.

Oh I didn't know there was such a disparity. Is there a water quality map somewhere?

Each utility should report water quality. For most of San Jose, it's

https://www.sjwater.com/sites/default/files/2021-06/ccr.pdf

The parameters relevant to plants (EC, pH, chloride, etc.) are usually in the secondary standards, rather than the primary standards most important for human health.

San Jose groundwater is terrible, EC ~ 700 uS/cm out of the tap. I wrote

https://hydromisc.github.io/hydromisc/doc/nutrient-calculato...

to model the custom fertilizer blend that I'm developing now, since the cal/mag in the water plus the phosphate from the acid I use to neutralize the carbonate significantly shift the nutrient profile. That's obviously beyond typical houseplant practice, but professionals growing in non-soil media (nurseries, vegetable growers, etc.) do roughly the same.

The peninsula gets Hetch Hetchy water, San Jose mostly uses Delta water, and the East Bay gets water from the Camanche Reservoir. Mostly, anyway.

EBMUD actually uses the Pardee Reservoir. But it's a trivial distinction because it's just upstream of the Camanche, both getting water from the Mokelumna watershed.

I think that's true about surviving versus thriving. I have a bonsai nursery and 'bonsai' is one area where there is a lot of serious interest. Lots of disagreements but a much higher rate of expert knowledge. Sometimes we have to remind ourselves what we want from our plants and adapt accordingly. Sometimes simple is better even when the results are less spectacular

> The Bay area has particularly nasty water

Bafflingly wrong, at least for the large majority of the Bay Area. It's Sierra runoff with very low TDS, hardness, or alkalinity.

Maybe your particular area has issues, but to generalize that to the bay area is objectively wrong.

Acidify your tap water with cooking vinegar - it helps.

Acetic acid is toxic to most plants. In fact it's used as a weed killer.

You can use citric or phosphoric acid though.

I believe you but I already use vinegar in small quantities for years just to bring the pH down to around 6. My plants thrive.

A study found that vinegar significantly slowed growth (vs. citric or phosphoric acid) in all three plant species tested:

https://sciendo.com/pdf/10.2478/johr-2019-0004

It may still be better than nothing, since they didn't test nothing. Citric acid was better than vinegar for them, but still showed worse yield than phosphoric. I tried citric acid myself and found that its pH down effect disappeared within hours, as some combination of the plant itself and the root zone microbiota broke down the citrate:

https://old.reddit.com/r/Hydroponics/comments/q4u5wz/gh_ph_d...

The professionals generally use mineral acids, and I believe that's with good reason. Of those phosphoric is the safest to handle, though a significant corrosive hazard in concentrated form; carefully dilute to ~2% for day to day use. You could also try monopotassium phosphate, but if your water is hard then you'd need such massive amounts that the extra K and P may become problematic.

Where do your get all this info from? This shit is fantastic. I’ve been scouring the wasteland of the internet for decent plant knowledge and seem to go from oasis to oasis in a vast desert of seo garbage

It's helpful to learn and use professional terminology, to get away from heavily SEO'd search terms. A search for "when to water potted plant" returns endless variations of the same mediocre article, but "coir irrigation frequency" returns good stuff.

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