Soil and Substrates
Potting mix is not soil from the ground — it is a structure. Its job is to hold water and air at the same time, hold the plant upright, and give roots something to grip. Garden soil in a pot compacts into a brick, and in Kuwait’s heat and hard water a badly chosen mix is the difference between a plant that grows and one that limps along for a year. This guide covers what goes into a mix, which mix suits which plant, and how to repot.
In 30 seconds
- A mix is a base that holds water plus an aggregate that holds air. The ratio decides which plant it suits.
- Aroids want roughly a third bark and a third perlite or pumice. Cacti want a gritty cactus mix.
- The white crust on the surface is salt from the tap water — scrape it off and flush the pot.
- Repot into a pot two to four centimetres wider, no more, and always one with a drainage hole.
- Between repots, top-dress: replace the top 2–3 cm instead of disturbing the roots.
What you need
- Potting soil — ready-made bases for green plants, cacti, herbs, citrus and flowers.
- Substrates — perlite, pumice, LECA, coir, bark and sand to adjust drainage.
- Potting mix — blended mixes for indoor plants and seed starting.
- Pots — and, specifically, pots with a drainage hole.
- Nutrition — fresh mix carries only a few weeks of feed.
- Garden hand tools — a scoop, a hand fork and gloves.
1. What a mix is made of
The one ruleThe base holds the water and the aggregate holds the air. Change the ratio and you change the plant it suits.
Almost every mix is a base that holds water, plus an aggregate that holds air. Change the ratio and you change the plant it suits.
| Ingredient | What it does | Use it when |
|---|---|---|
| Peat / coco coir | The water-holding base. Coir rewets more easily than peat once dry. | Every general mix. |
| Perlite | White volcanic granules. Air pockets, very light, floats to the top over time. | You want faster drainage without extra weight. |
| Pumice | Heavier mineral grit. Same air as perlite but stays put and adds stability. | Tall plants, aroids, anything top-heavy. |
| Bark / orchid chips | Chunky structure, breaks down slowly. | Aroids, orchids, hoyas — roots that want to climb, not sit. |
| LECA / clay pebbles | Inert, reusable, drains almost instantly. | Semi-hydro, self-watering pots, a drainage-free cover pot layer. |
| Coarse sand | Weight and sharp drainage. Not builder’s sand. | Cacti and succulents. |
| Worm castings / compost | Slow nutrition and biology. | Edibles, herbs, outdoor beds. |
| Mycorrhizal fungi | Extends the root system’s reach for water and phosphorus. | At repotting, dusted directly on the roots. |
2. Which mix for which plant
The one ruleIf the mix looks like something you would use in a flower bed, it is too dense for an indoor pot.
Aroids — monstera, philodendron, anthurium, alocasia
These grow up trees in the wild; their roots want air. Start from a green-plant soil and add roughly a third bark and a third perlite or pumice by volume. If the mix looks like something you would use in a flower bed, it is too dense.
Cacti and succulents
Use a dedicated cactus soil, then cut it further with 30–50% pumice or coarse sand. In Kuwait’s summer an indoor succulent in a peat-heavy mix stays wet for weeks and rots at the base.
Calathea, maranta, ferns
These want steady moisture without sogginess: a green-plant soil with about 20% perlite and a little coir. Never let this group dry out completely.
Herbs, seedlings and vegetables
A fine, low-nutrient seed-starting mix for germination, then a herb or vegetable soil once the first true leaves appear. See herb seeds and vegetable seeds.
Outdoor pots, palms and olives
Weight matters here — a light peat mix blows over and dries out in an afternoon. Use a heavier potting soil with sand or pumice, and mulch the surface.
Orchids
Bark and sphagnum only. Orchid roots in potting soil suffocate within weeks.
3. Kuwait-specific problems and fixes
The one ruleThe white crust is salt, not mould — scrape it off and flush the pot.
The white crust
Hard, alkaline tap water (around pH 7.5–8) leaves salts behind every time the water evaporates. In a hot, dry climate that happens fast, so the crust builds faster here than in most places. Scrape off the crusted top centimetre, replace it with fresh mix, and flush the pot monthly — see the watering guide.
Alkaline mix, locked-out iron
Repeated hard-water irrigation slowly pushes the mix pH up. New leaves then come out yellow between green veins even though there is iron in the pot. Refreshing the mix resets it; agricultural gypsum or sulphur lowers pH gradually on outdoor beds and large pots.
Hydrophobic, shrunken mix
A peat-based mix that has completely dried in summer repels water — you water and it runs straight down the gap at the pot wall. Stand the pot in a basin for 20–30 minutes to rewet from below, then poke a few holes in the surface with a chopstick. Coir-based mixes are far more forgiving in this climate.
Heat at the roots
Dark plastic pots in summer sun can reach root-killing temperatures. Use light-coloured or terracotta pots outdoors, group them so they shade each other, and mulch the surface to slow evaporation.
Fungus gnats
They breed in permanently damp organic surfaces. Let the top layer dry between waterings, or top-dress with a centimetre of pumice or coarse sand — the adults cannot lay in it. See biological pest control.
4. Repotting, step by step
The one ruleGo up two to four centimetres in diameter, no more, and always into a pot with a drainage hole.
Signs it is time: roots circling out of the drainage hole, water running straight through, the plant drying out within a day or two, or growth that has simply stopped in a season it should be growing.
- Pick the pot. Two to four centimetres wider in diameter than the current one, no more. A pot that is much too big stays wet in the middle where there are no roots. It must have a drainage hole.
- Water the plant the day before. A hydrated root ball comes out in one piece.
- Pre-moisten the new mix in a bucket until it is damp, not dripping. Dry peat will not absorb water once it is in the pot.
- Slide the plant out. Squeeze the pot, tip it and support the stem. Never pull the plant by the stem.
- Inspect the roots. Healthy roots are firm and pale. Cut away anything brown, hollow or smelling sour with clean scissors. Loosen any tight circling roots at the bottom.
- Dust with mycorrhizal fungi if you are using it — it needs contact with the roots.
- Set the depth. A few centimetres of mix underneath, plant sitting at the same depth it grew at, and 2 cm of space below the rim so you can water without overflow.
- Fill and firm gently. Tap the pot on the table to settle the mix rather than compressing it with your hands.
- Water thoroughly until it drains, then drain fully.
- Wait. No fertiliser for four to six weeks — fresh mix already contains a starter charge — and keep the plant out of direct sun for a week or two.
Do not put gravel in the bottom “for drainage”. It does the opposite: water sits at the boundary between the fine mix and the coarse layer and raises the wet zone into the roots. Use a pot with a drainage hole instead. Gravel or LECA in the bottom of a cover pot, with the nursery pot standing on top, is a different thing and is fine.
When not to repot
Do not repot in the middle of a heat event, do not repot a plant that is already sick from overwatering into a bigger pot — go smaller with fresh airy mix — and do not repot a plant that has just arrived. Give a new plant two to three weeks to settle first.
5. Refreshing without a full repot
The one ruleTop-dressing removes the salts and restores nutrition without touching a single root.
Most indoor plants only need a true repot every 18 to 24 months. In between, top-dress: scrape off the top 2–3 cm of old, crusted mix, replace it with fresh, and resume feeding. It removes accumulated salts, restores some nutrition and does not disturb the roots at all.
Questions we get asked
Can I use garden soil from outside?
No. In a pot it compacts, drains badly and brings in weed seed and pests. Kuwait’s ground is also typically sandy, alkaline and salty.
How often should I change the mix?
Every 18–24 months for most indoor plants, or sooner if it is crusted, water-repellent or smells sour. Top-dress in the intervening year.
Perlite or pumice?
Same job. Perlite is lighter and cheaper but migrates to the surface; pumice is heavier, stays mixed and steadies tall plants. In summer heat pumice also holds a little more moisture at the root.
What is the best time of year to repot in Kuwait?
Late February through April, and again in October. Avoid the peak of summer.
Do I need to sterilise the mix?
Not for a bagged commercial mix. Reused mix from a plant that died of root rot should be discarded, not reused.
Can I reuse LECA?
Yes. Rinse it, soak it in clean water and let it dry between uses.
Continue with the other care guides
Everything linked here is stocked by NABAT and delivered across Kuwait in 1–4 business days. Free delivery over 10 KD.