Tap vs Distilled vs Filtered Water for Plants: Which is Best Water?

Have you noticed brown leaf tips when you water your plants, white crust on the soil surface, or white residue in your watering kettle? Often, these issues are directly related to the kind of water you use and the water for your plants.

For most indoor plants, distilled or RO water isn’t necessary: simply filtered tap water is safe, retains beneficial minerals, and is convenient to use. This guide will focus on how to choose and use filtered water to keep your plants healthy, while also explaining when distilled or RO water might be appropriate in special cases.

Why Water Quality Matters for Plants

Tap water often contains chlorine or chloramine, dissolved minerals like calcium and magnesium (hardness), fluoride, and sometimes trace amounts of other water contaminants or chemicals in your home water supply. While these additives are generally safe for human consumption, they can affect plant health in subtle but noticeable ways. According to the U.S. Environmental Protection Agency (EPA), chloramine is widely used in municipal water systems as a disinfectant because it remains stable longer than chlorine and effectively prevents microbial growth in drinking water. However, water that is too hard or water contains high levels of chlorine can lead to several issues for plants and may even harm your plants over time:

Brown or crispy leaf tips – caused by chemical stress or salt accumulation at the edges of leaves.
White crust on the soil surface – a buildup of salts from minerals in hard water, which can interfere with water absorption.
Root stress or stunted growth – excess minerals or chlorine can disrupt nutrient uptake, slowing overall plant development.

Using filtered water for plants helps mitigate these problems because activated carbon filters and other water filters remove most harmful chemicals while retaining beneficial minerals like calcium and magnesium. This provides a safe, balanced water source that supports healthy growth, vibrant leaves, and strong roots for a wide variety of indoor plants.

Best water for plants: distilled vs tap vs filtered vs RO vs rainwater

Different types of water vary in purity, mineral content, and chemical composition. Choosing the right source of water for plants can directly affect plant growth and health. Here’s a detailed look at each type:

1. Filtered Water (Carbon / Catalytic Carbon)

TDS: 50–500 ppm (varies with filter and tap water quality)
What it removes: Chlorine, some volatile organic compounds (VOCs), some metals; catalytic carbon can also reduce chloramine.
What it leaves: Most beneficial minerals like calcium and magnesium remain, supporting healthy leaf and root development.
Best use: Ideal for most houseplants, including fussy tropicals and herbs. Filtered water is often the most practical choice and is generally the best for your plants, making it easy and convenient to use when you water your plants daily. A simple water filtration setup ensures consistent, high-quality water for indoor greenery.
Practical tips: Replace filters regularly, avoid using exhausted cartridges, and for very sensitive plants, consider blending with a small percentage of RO/distilled water.

2. Tap Water

TDS: 50–800+ ppm (depends on local supply)
What it removes: Nothing by default; chlorine may off-gas if water sits, but chloramine remains.
What it leaves: Naturally occurring minerals plus chlorine or chloramine; can be beneficial or harmful depending on hardness and chemical content.
Best use: Suitable for hardy houseplants that tolerate moderate chemicals and mineral levels. Avoid plants with softened water if your tap water has added sodium or other treatment chemicals.
Practical tips: Test local water hardness and TDS from your home water supply; let chlorine off-gas for 24h; consider using a basic carbon filter as part of a simple water filtration system if chlorinated; avoid sodium-softened water.

3. Distilled / RO Water

TDS: 0–30 ppm
What it removes: Almost all minerals, salts, chlorine, chloramine, and most dissolved solids.
What it leaves: Essentially pure H2O, which prevents chemical stress but provides no nutrients.
Best use: Sensitive species (Calathea, Maranta, orchids), seedlings, cuttings, hydroponics, and semi-hydro systems. Distilled and filtered water, including water from reverse osmosis systems and water distillers, is ideal in these cases.
Practical tips: Always supplement with calcium, magnesium, and a complete fertilizer. Blend a small amount of filtered tap water if needed for pH buffering.

4. Rainwater

TDS: 10–50 ppm
What it removes: Naturally low in minerals; usually free of chlorine and many chemicals.
What it leaves: Very soft water; minimal minerals.
Best use: Safe for most plants if collected and stored cleanly; especially good for sensitive or chemical-sensitive species.
Practical tips: Avoid collecting from roofs that may introduce contaminants. Store in covered containers to prevent algae and mosquito growth. Rainwater also offers a naturally soft alternative when your tap water is too hard or chemically treated.

Composition snapshot: minerals, chemicals, and TDS ranges

Different waters carry different loads. The key differences are minerals (like calcium and magnesium), disinfectants (chlorine, chloramine), and total dissolved solids. Here’s a quick comparison you can use to pick the right match.

Water Type	Typical TDS (ppm)	What It Removes	What It Leaves	Best Use	Cautions
Distilled	0–10	Chlorine, chloramine, metals, minerals, most organics	Almost nothing	Sensitive plants, seeds, hydro/semihydro	Must add nutrients; little buffering
RO	0–30	95–99% of dissolved solids, chlorine/chloramine with proper prefilter	Very little	Hydro/semihydro, sensitive plants, hard water areas	Wastewater, maintenance, must remineralize
Filtered (carbon/catalytic)	50–500 (varies)	Chlorine; catalytic carbon reduces chloramine; some VOCs/metals	Many minerals remain	Most houseplants	Change filters on time; may not fix very hard water
Tap	50–800+ (varies by city)	None by default	Minerals, chlorine or chloramine, possibly fluoride	Tough houseplants	May cause tip burn in sensitive plants; varies widely
Rainwater	10–50 (varies)	N/A	Very low minerals; some dissolved CO2	Most plants, if clean	Air pollution, roof debris; store safely

Pros and cons by water type

Distilled and RO are clean and consistent. They remove the main sources of chemical stress and stop salt crust from forming. The trade-off is the need to add back calcium, magnesium, and other nutrients. In soil, you’ll often feed at a quarter to half strength each time you water during active growth. In hydro or semi-hydro, you’ll set precise nutrient levels.
Tap is easy and cheap. It brings some minerals plants can use. But if your tap is very hard or carries chloramine, sensitive plants may show browning tips or slow growth. Sodium-softened tap water is a no-go for all plants.
Filtered water for plants(through activated or catalytic carbon) takes out chlorine and many unwanted compounds while keeping a lot of minerals. For most indoor plants, this is a practical balance. Catalytic carbon can also reduce chloramine, which plain carbon doesn’t fully handle.
Rainwater is soft and gentle. Many plants love it. Just keep the collection system clean and covered, and follow your local rules.

Data highlights to inform your choice

University and government sources explain that chlorine and chloramine are added to protect drinking water. That’s good for people, but some houseplants react to these chemicals and to high salts. Extension specialists note that switching water can reduce leaf tip burn. A controlled study showed that plants watered with near-zero TDS water grew poorly without nutrients, while moderate TDS supported better growth. Another study found that when water had fewer harmful ions, growth improved in both shoots and roots. These findings align with grower experience: many report that calatheas, orchids, and dracaenas stop browning once they switch to distilled or filtered water and feed on a steady schedule.

If you’re wondering what kind of water is best for plants in your space, the evidence suggests a match: use cleaner water for sensitive species and systems where you want control (like hydro), and use filtered or mild tap for tough plants that are not reacting.

Can you water plants with distilled water? Plant-by-plant guidance

Is distilled water good for plants? You can water almost any plant with distilled water if you also supply nutrients. The key is to match the water to the plant’s needs and your potting setup.

Sensitive “finicky” plants and special cases

Many Aroids and tropicals that come from humid forests prefer softer water. Calatheas, marantas, and fittonias often show crispy tips when watered with hard, chlorinated tap. Distilled water for plants like these removes the stress point, and you’ll often see new leaves emerge cleaner and larger after a few weeks. Orchids also respond well to soft water because bark-based media can load up with salts over time. African violets maintain smoother leaf edges and better blooms when watered with soft, clean water. Carnivorous plants need mineral-poor water because they evolved in nutrient-poor bogs; use distilled, RO, or clean rain, and feed prey to the traps rather than fertilizing the soil.

Seedlings and cuttings are fragile. Distilled water reduces pathogens and salt stress. Begin with plain distilled water; once true leaves appear, feed at very low strength so roots can adapt.

A quick example: my own calathea orbifolia kept crisping no matter how I tweaked light and humidity. I switched to distilled water plus a tiny dose of calcium and magnesium once a month. Within one growth cycle, new leaves opened without brown edges, and the soil surface stopped forming white crusts.

Tough houseplants and edibles

Pothos, snake plants, ZZ, philodendrons, spider plants, and many succulents usually tolerate tap water, especially if it is not very hard and contains chlorine rather than chloramine. If you notice build-up or browning, move to filtered water. For kitchen herbs and leafy greens grown in pots, filtered or RO water with a small nutrient boost keeps flavor and texture consistent. If your tap has a strong chemical odor or leaves white flakes on the soil, step up to filtered or distilled/RO.

Hydroponics and semi-hydro (LECA/pon)

Hydroponics and semi-hydroponics work best with RO or distilled water because you control all nutrients. Pure water lets you hit precise electrical conductivity (EC) targets and pH levels. Always add calcium and magnesium to pure water before your base fertilizer unless your fertilizer includes them. Keep pH in the ideal range for your system so roots can take up nutrients.

EC/TDS targets vary by crop, but here are general guides:

System/Stage	Target EC (mS/cm)	Approx. TDS (ppm, 0.5 scale)	pH Range
Seedlings/clones	0.3–0.6	150–300	5.8–6.2 (hydro); 6.0–6.8 (soil)
Leafy greens	0.8–1.4	400–700	5.8–6.2
Fruiting crops	1.5–2.5	750–1250	5.8–6.2
Houseplants (semihydro)	0.6–1.2	300–600	5.8–6.2

Filtered Water for Plants: Benefits, Types, and Buying Guide

Filtered water is one of the simplest ways to improve water quality for indoor plants, offering a balance between purity, minerals, and convenience. Here’s everything you need to know:

Benefits of Filtered Water for Plants

Removes chlorine and most organic contaminants: Activated carbon water filters and other media reduce chemicals and volatile compounds that can stress plants or even be harmful to plants over time. Choosing the right water treatment method you choose ensures that you need to filter the water appropriately for your plant types.
Retains beneficial minerals: Calcium, magnesium, and other naturally occurring minerals remain in the water, supporting healthy leaf and root development.
Economical, convenient, and eco-friendly: Filtering tap water at home is cheaper and generates less plastic waste than buying bottled distilled or RO water.
Suitable for most indoor plants: From tropicals and herbs to common houseplants, filtered water provides safe and balanced hydration for everyday plant care.

Types of Filters

Carbon Filters (Pitcher or Under-Sink)

Remove chlorine and improve water taste.
Retain essential minerals for plant health.
Affordable and easy to use for most household plants.

Catalytic Carbon

Specially designed to break down chloramine, which standard carbon filters cannot fully remove.
Ideal in cities that use chloramine-treated water.

Ion Exchange Filters

Reduce hardness ions like calcium and magnesium partially.
Helpful if tap water is very hard, but still leaves some beneficial minerals.

Reverse Osmosis (RO) Systems

Provide nearly pure water, removing almost all dissolved solids.
Best for highly sensitive plants, seedlings, or hydro/semi-hydro systems where precise nutrient control is required.
Requires supplementation with calcium, magnesium, and a complete fertilizer.

Buying and Usage Tips

Check NSF/ANSI Certifications: Look for filters certified under 42 (taste/odor), 53 (health-related contaminants), or 401 (emerging contaminants). Certifications ensure the filter has been tested for effectiveness.
Replace cartridges regularly: Old or exhausted filters can leach trapped contaminants back into water.
Choose the right filter for your plants: For most houseplants, a simple carbon filter is enough—low cost, easy to use, and effective. RO or catalytic systems are only necessary for sensitive species or very hard/chloramine-heavy water.

Bottom line: For the majority of indoor plants, filtered water strikes the perfect balance—removing harmful chemicals while keeping beneficial minerals, convenient, cost-effective, and environmentally friendly.

can you water plants with distilled water

Is RO water good for plants? When to choose RO

Reverse osmosis water is very similar to distilled water in practice: low TDS, low contaminants, and predictable. Is RO water good for plants? Yes—especially if you need a clean slate for nutrients or your tap is harsh.

Benefits and drawbacks

RO gives you nearly pure water on demand. It’s consistent, which makes plant care simpler. Sensitive species thrive without chemical stress. Hydroponic growers prefer RO because they can set exact EC and pH. The trade-offs are water waste (which you can reuse elsewhere), costs for filters and membrane, and the need to add back calcium, magnesium, and nutrients.

Best-use scenarios

Very hard water areas where white crust forms quickly on soil
Cities that use chloramine and where simple off-gassing doesn’t work
Salt-sensitive species, orchids, or plants in bark or semi-hydro
Hydroponic systems where you manage nutrients closely

How to remineralize RO properly

Start with RO water in a clean container or reservoir.
Add calcium and magnesium first to reach a small baseline (for soil, many aim near 50–100 ppm Ca+Mg total; for hydro, follow your nutrient line’s directions).
Add your complete fertilizer to reach target EC or the soil-feeding strength you prefer.
Adjust pH last. For hydro and semi-hydro, aim 5.8–6.2. For soil, aim 6.0–6.8.
Optional: add a small percentage of filtered tap water if you need extra alkalinity for pH stability.

Is RO water too pure for plants?

Pure water is not a problem by itself. Plants need minerals, but they don’t have to come in the water naturally. If you add nutrients and small amounts of calcium and magnesium, RO water supports great growth. “Too pure” only becomes an issue if you skip minerals and run long stretches with 0 ppm water and no fertilizer.

Nutrient management for distilled/RO water (remineralize for growth)

Before diving into the specifics of nutrient management, it’s important to understand why minerals matter for your plants. Even with clean distilled or RO water, plants won’t thrive if they’re missing the building blocks for growth. This section will guide you through how to remineralize distilled/RO water, what nutrients to prioritize, and simple strategies to keep your plants healthy, vibrant, and growing strong.

Why minerals matter

Plants need more than water and light. Calcium builds strong cell walls and healthy root tips. Magnesium sits at the center of chlorophyll, so it powers photosynthesis. Potassium helps open and close stomata so leaves can breathe. When you use distilled or RO water without adding nutrients, plants can show weak new leaves, curled tips, pale areas between veins (interveinal chlorosis), and slow roots. Remineralizing solves this and keeps growth even.

Remineralization options

You have three simple routes:

Add a Cal-Mag supplement to bring calcium and magnesium back into pure water, then use a complete fertilizer at low strength.
Use a complete fertilizer that already includes calcium and magnesium. Many balanced houseplant or hydroponic nutrients do.
Blend a small amount of safe tap or clean rainwater into distilled/RO to raise TDS and buffering. This is handy if your fertilizer is soft on calcium or if your pH swings.

Soil amendments can also help buffer long term. Gypsum adds calcium without raising pH much. Dolomite lime adds calcium and magnesium and raises pH in acidic mixes. Use them as directed, and retest pH after a few weeks.

Feeding targets and schedules

A simple plan beats guesswork. In soil mixes, aim for light, regular feeding during the growing season rather than heavy doses once in a while. In hydro or semi-hydro, use a meter if you can. The ranges below keep plants safe while giving room to adjust.

Context	Frequency	Strength/Target
Soil-grown houseplants	Every 2–4 weeks in growth	1/4–1/2 label strength; pH 6.0–6.8
High-demand houseplants (active)	Weekly, small dose	1/8–1/4 label strength; pH 6.0–6.8
Semi-hydro in LECA	Maintain nutrient reservoir	0.6–1.2 EC (300–600 ppm); pH 5.8–6.2
Hydroponic leafy greens	Maintain solution	0.8–1.4 EC (400–700 ppm); pH 5.8–6.2

Tip: If leaves pale after switching to pure water, increase magnesium slightly. If new leaves twist or stick, check calcium and total EC. If you see salt crust on top of soil, flush with clean water until runoff EC drops, and reduce feed strength.

How to make tap water safe for plants (step-by-step)

Tap water varies a lot by city. Some supplies are gentle. Others are very hard or use chloramine rather than chlorine. A few checks tell you what you have and what to do next.

Decode your local water

Check your city’s water quality report. Look for disinfectant type (chlorine vs. chloramine), hardness (as CaCO3), TDS, and pH.
Test at home if you can. A simple TDS meter gives a quick number. GH/KH aquarium kits show hardness and alkalinity. Your nose helps too—if you smell chlorine, there’s free chlorine present.
Note any plant signals. Tip burn, white crust, and slow growth under tap water suggest you should filter or switch to distilled/RO.

Simple treatments and their limits

Let water sit 24 hours to off-gas chlorine. This does not remove chloramine.
Boil for 15 minutes and let cool to remove chlorine faster. Again, this won’t fix chloramine.
Aerate with an aquarium bubbler to speed chlorine loss. Still not effective for chloramine.
Use activated carbon to reduce chlorine and many organics. For chloramine, use catalytic carbon. This provides a standalone solution for your plants, rather than watering without filtering the water first, which could stress sensitive species.
Where allowed, Campden tablets (potassium metabisulfite) can neutralize chloramine quickly. Use the smallest effective dose, and mix well.

Filters that work for plants

A basic pitcher or under-sink carbon filter reduces chlorine, tastes, and odors and often lowers some metals. Catalytic carbon works better on chloramine. Ion exchange media can reduce hardness in some pitchers, though they may swap ions. For large collections, a point-of-use system with sediment, carbon/catalytic carbon, and optional RO can give you consistent water. If you have a whole-house softener that uses sodium, bypass it for plant water or use a separate tap that feeds pre-softened water to a filter. Sodium is harmful to many plants.

Is filtered water from the fridge good for plants? If the filter uses activated carbon and your city uses chlorine, yes, it often helps. If your city uses chloramine or your water is very hard, a stronger filter (catalytic carbon or RO) is more reliable. Always replace cartridges on schedule.

Water filter for plants: features and smart picks

A good water filter for plants is about matching media to your water and your plant mix. Here’s what matters.

Media and mechanisms (what each removes)

Activated carbon grabs chlorine, many volatile organic compounds (VOCs), and improves taste and odor.
Catalytic carbon targets chloramine more effectively than standard carbon by promoting chemical breakdown.
Ion exchange can reduce hardness or specific ions, depending on the resin type.
Sediment filters catch rust, sand, and silt that clog finer media.
RO membranes reject 95–99% of dissolved solids, including many salts and metals. They need carbon prefilters to protect the membrane from chlorine/chloramine.
UV can inactivate microbes, useful for rainwater or well water feeding edible crops, though most indoor setups don’t need UV if the source is municipal.

Look for NSF/ANSI certifications that match your goals: 42 (taste/odor/chlorine), 53 (health claims for specific contaminants), and 401 (emerging compounds). Certifications tell you what a filter has been tested to remove.

Mineral retention vs removal

For soil-grown houseplants that are not fussy, keeping some calcium and magnesium is helpful. A carbon filter that leaves minerals in place can be ideal. For hydro or semi-hydro, or if you care for many sensitive plants, stripping minerals with RO or using distilled water puts you in control. You can also blend filtered water with RO/distilled to hit your target TDS for a custom mix.

Ownership costs and upkeep

Replace carbon and sediment filters on time. Old carbon can release what it trapped.
RO systems have higher upfront cost and waste some water, but provide near-pure water and stable TDS. You can reuse RO wastewater for cleaning or outdoor, non-edible plants.
Pitchers are low cost but need regular cartridge changes and have limited flow.

A simple way to compare options for indoor plant care:

Filter Type	Removes Best	Keeps Minerals?	Cost/Gallon (approx.)	Best For
Pitcher (carbon)	Chlorine, some VOCs/metals	Yes	Low–medium	Most houseplants on chlorinated tap
Under-sink (catalytic + sediment)	Chlorine and chloramine	Yes	Medium	Houseplants on chloramine tap
RO system	Most dissolved solids	No	Medium–high	Hydro/semihydro, sensitive plants, very hard water
Whole-house carbon	Chlorine/chloramine at all taps	Yes	Varies	Large plant collections; convenience

Troubleshooting: leaf tip burn, salt crust, and slow growth

When leaves crisp or soil crusts form, water quality is often part of the story. Here’s how to read the signs and act.

Diagnose by symptom

Tip or edge burn points to chemical stress (chlorine or chloramine), fluoride sensitivity (common in dracaena and some palms), or salt buildup in the pot. Pale leaves with green veins hint at magnesium or iron issues. Stunted new growth or distorted tips can signal low calcium, high EC, or poor aeration in the mix.

If you see white, chalky crust on top of the soil or along pot rims, that’s salt. It can come from hard water or heavy feeding. Both can be fixed.

Fixes that work

Flush containers. Water thoroughly with clean, low-TDS water until lots of runoff drains out. Repeat in a week if crust is heavy.
Switch water type. Try filtered water for plants if you use tap. For sensitive plants, switch to distilled or RO and feed lightly.
Reset nutrients. Lower fertilizer strength, and add a small Cal-Mag dose if new growth looks weak.
Set pH in range. Use a simple pH test kit or strips to confirm.
Repot if needed. If the surface is caked with salts or the mix has broken down, repot into fresh, airy medium.

Evidence and case studies

Extension educators note that chlorine and chloramine, while safe for drinking, can be rough on sensitive houseplants. Browning tips and margins often improve after a switch in water type. A study on TDS found that plants watered with near-zero TDS grew very poorly without added nutrients, while plants at modest TDS performed best. Another peer-reviewed paper linked cleaner water to better shoot and root development when harmful ions were minimized. These findings match the community experience: calathea leaf edges soften, orchids put out better roots, and dracaenas stop browning when you remove the chemical load and keep nutrition steady.

Summary and action plan (choose, supplement, succeed)

You don’t need a lab to pick the right water. Use a simple plan, watch your plants, and adjust.

Quick rules of thumb

For sensitive plants and seedlings, distilled or RO water is a safe starting point. Add light, regular nutrients.
For most houseplants, filtered tap water reduces chemical stress and keeps useful minerals. If you see browning or crust, move up to cleaner water.
Avoid sodium-softened water. If your home has a softener, draw water before the softener or use filtered RO/distilled for plant care.
Clean rainwater is great when caught and stored safely.

Weekly and monthly routine

Water with your chosen source and feed lightly during active growth.
Once a month, test TDS and pH if you can, and flush pots until runoff EC drops.
Inspect leaves for tip burn or pale areas. If you see issues, adjust water type or feeding.
Replace filter cartridges on schedule. Old filters can leach what they trapped.

Cost and sustainability tips

Compare cost per gallon across options. Distilled jugs cost more per gallon than RO at home; filtered tap is often the cheapest. Clean, collected rainwater may be free where legal.
Reuse RO wastewater for mopping, flushing, or watering non-edible outdoor plants.
Keep lids on stored water and rain barrels to prevent algae and mosquitoes.
Rinse or replace trays and reservoirs regularly to keep biofilm low.

FAQs

1. What kind of water is best for plants?

Well, it really depends on the type of plants you have and the quality of your tap water. For sensitive houseplants like calatheas, marantas, orchids, or any seedlings and cuttings, distilled or RO water is usually the safest bet—but make sure to add nutrients, because pure water alone won’t give them what they need to grow strong. On the other hand, most “tough” houseplants—like pothos, snake plants, ZZ plants, or spider plants—are perfectly happy with filtered tap water. Filtered water removes harsh chemicals like chlorine while keeping useful minerals that help plants thrive, so it’s convenient and works for everyday watering.

2. Do plants prefer distilled or purified water?

Many sensitive plants do prefer distilled or RO (purified) water because it’s free from chlorine, chloramine, salts, and other chemicals that can stress them out. Think of it as giving them a clean slate. But don’t forget—if you’re using distilled water all the time, you need to feed them regularly with a good fertilizer that provides calcium, magnesium, and other nutrients. Otherwise, their growth can slow down, leaves might pale, and new roots could struggle.

3. Is filtered water from the fridge good for plants?

Usually, yes—if your city water contains just chlorine, the fridge filter does a decent job removing it, and your plants will be fine. However, if your water contains chloramine (which doesn’t evaporate easily) or is very hard with lots of dissolved minerals, fridge filters won’t cut it. In that case, a stronger filter like catalytic carbon or an RO system is a safer choice for your sensitive plants, especially if you notice brown leaf tips or white crust on the soil.

4. How do you make tap water safe for plants?

First, find out what’s in your tap water—check if it has chlorine or chloramine and how hard it is (high calcium and magnesium can make it “hard”). For chlorine, you can just let the water sit for 24 hours to off-gas, or boil it briefly. Chloramine is trickier—it won’t go away on its own, so you’ll need catalytic carbon filters, RO, or neutralizing tablets to remove it. If your tap water is very hard, you can switch to filtered water, distilled, or RO for watering sensitive plants. Basically, the goal is to remove or reduce chemicals that stress plants while keeping or supplementing the minerals they need.

5. Is it okay to use RO water for plants?

Absolutely! RO water is excellent for sensitive houseplants, seedlings, and hydroponic setups because it gives you a clean slate without any salts or chemicals that can harm roots. The key is to remineralize it—add calcium and magnesium, and use a complete fertilizer to supply other nutrients. Don’t forget to adjust the pH for optimal nutrient uptake—soil-grown plants like 6.0–6.8, while hydroponics do best around 5.8–6.2. Once you do that, RO water can actually make plant care more predictable and give you healthy, lush growth.

References

https://www.epa.gov/dwreginfo/chloramines-drinking-water