I believe the biggest culprit to plant death is watering - either forgetting/ignoring for weeks (me in the past), or going overboard. This module is about getting watering right.

Best Types of Water to Use

Not all water is equal. Ranked roughly best to worst for most plants:

• Rainwater — the gold standard. Naturally soft, slightly acidic, and free of the additives in city water. Collect it if you can.
• Filtered water (carbon filter, e.g. a Brita) — removes chlorine, but not chloramine. A great everyday choice if pH is adjusted.
• Distilled / reverse osmosis (RO) — super pure and great for all plants with neutral pH. These options are stripped of minerals, so you may need to supplement with some coconut water (magnesium, potassium and sodium), or sea salt (high in minerals).
• Tap water — usually fine for most plants if pH is adjusted (see below), contains calcium and magnesium, but can have flouride and chlorine/chloramine which is no bueno.
• Softened water (from a salt-based water softener) — avoid it. It swaps hardness minerals for sodium, which builds up and slowly poisons plants.

Tap Water: The Pros & Cons

Tap water gets a bad rap, but it's more nuanced than that.

The good: it often carries useful minerals and small amounts of nitrates and phosphates — which are literally plant nutrients. It's cheap, convenient, and for most hardy houseplants it's completely fine.

The not-so-good:

• Chlorine & chloramine — added to disinfect city water. Chlorine will off-gas if you let water sit out uncovered for 24 hours. Chloramine is more stable and won't simply evaporate — it needs a carbon filtration or a water conditioner (check your municipal water additives online).
• Pharmaceutical residues & other contaminants can be present in trace amounts.
• High pH — lots of municipal water runs alkaline (pH 7.5–8.5+), which over time can lock out nutrients (see pH section). Where I live, it’s consistently 10+ which will prevent plants from growing at all.
• Sodium — only an issue if it's run through a water softener.

Bottom line: for most plants, tap is usually fine. Letting it sit out overnight or running it through a simple carbon filter handles most of the downsides and then you just need to adjust the pH. I always use RO water because I use it to make our products, but in a pitch or to get some minerals in my soil I’ll use pH adjusted tap water.

Water pH: What It Does & How to Test It

pH measures how acidic or alkaline your water is, on a scale of 0–14 (7 is neutral). It matters because pH controls which nutrients a plant can actually absorb. Even in perfectly fed soil, the wrong pH "locks out" nutrients and the plant starves in a full pantry. Most houseplants are happiest around 6.0–6.8 — slightly acidic, but shoot for neutral and your soil microbes will handle the rest. Plus, our products are slightly acidic.

Testing it with butterfly pea flower 🦋