Everything we know about growing well in a bag.

Every GrowBag has a built-in water reservoir at the base, separated from the growing medium by a wicking layer. You fill the reservoir through the side fill-tube, and the fabric draws moisture upward as the ProSoil above it dries out — the same principle as a wick lamp pulling oil up to the flame. Roots grow down toward that moisture instead of sitting in it, which is what keeps them from rotting the way they can in a waterlogged pot.

In Nairobi's climate this changes your watering rhythm more than almost anything else you'll do. During the long rains (March–May) and short rains (October–December), you may not need to top up the reservoir at all for a week or more. In the dry, sunny stretches of January–February and June–September, plan to check the fill-tube every 3–4 days for smaller bags and once a week for the Large and Extra-Large sizes.

• Check the reservoir by looking down the fill-tube — if you can't see water, top it up.
• Never pour water directly onto the soil surface as your main watering method; use the fill-tube so the reservoir does its job.
• An overflow hole near the top of the reservoir stops it from drowning the roots — if water runs straight back out, it's already full.

The smallest tier in the range, and the easiest place to start if you've never grown anything in a container before. It sits comfortably on a windowsill, a kitchen step, or a narrow balcony rail shelf, and the Compact variant is built specifically for spaces where footprint matters more than volume — think apartment balconies or shared courtyards.

What grows well: coriander (dania), spring onions, mint, basil, rosemary, and loose-leaf salad greens like lettuce and rocket. Anything you harvest a little of at a time rather than one big crop at the end.

Sow seeds directly into moist ProSoil at roughly the depth of the seed itself — as a rule of thumb, cover a seed with soil no deeper than twice its own width. Thin seedlings once they have their first true leaves so the strongest ones aren't competing for the same root space; overcrowding is the single most common reason Mini bags underperform.

A step up in root room, and the tier we recommend most often to first-time vegetable growers. It handles single plants that need more depth than herbs but don't yet demand the full spread of a Standard bag.

What grows well: dwarf and determinate tomato varieties, chillies and bird's-eye pepper, capsicum, and dhania grown as a fuller crop rather than a windowsill garnish.

• One tomato or capsicum plant per bag gives the best yield — resist the urge to plant two "just in case."
• Stake or cage tomato varieties early; roots establish fast in ProSoil and top growth can outpace an unsupported stem within three to four weeks.
• Pinch out the lowest side shoots on tomatoes once the plant passes knee height to keep energy going into fruit rather than foliage.

Our most popular size for a reason — it's the smallest bag that comfortably grows kale (sukuma wiki) as a proper cut-and-come-again crop, and it has enough soil volume to buffer against the odd missed watering.

What grows well: sukuma wiki, managu, terere (amaranth), full-size capsicum, and compact courgette varieties.

For sukuma wiki specifically: harvest the outer, lower leaves first and leave the growing tip at the top intact. Done this way, a single Standard bag can keep producing for two to three months before it's worth replacing the plant. Feed lightly with compost tea or a diluted organic feed every two to three weeks once you start harvesting — continuous cutting draws down nutrients faster than a plant grown for a single harvest.

These two sizes are built for crops with a real root system: eggplant (biringanya), full-size tomato varieties left to sprawl, cucumbers grown along the ground, and — in the Extra-Large — squash and pumpkin, which will happily send vines out over the bag's edge and along a trellis or fence you provide separately.

Because there's more soil mass, these bags hold moisture longer and are more forgiving if you're away for a few days, but that same mass means the reservoir takes longer to fill and drain, so give it a minute after topping up before checking whether it's full.

• Extra-Large bags can support a perennial like a dwarf passion fruit or a chilli bush left to grow year-round rather than replanted each season.
• Top-dress with a handful of compost every four to six weeks during active fruiting — big fruiting crops draw down ProSoil's nutrient charge faster than leafy crops.
• Rotate what you grow in a Large or Extra-Large bag each season where possible; tomatoes and capsicum are both in the nightshade family and repeated planting invites the same soil-borne issues.

Built for climbers, and the best option when floor space is the scarce resource rather than soil volume. The Vertical variant uses the same footprint as our Standard bag but is paired with a taller support pocket at the back, so a trellis, cane wigwam, or wall-mounted mesh has something to anchor to.

What grows well: passion fruit (grown as a compact espalier rather than left to run wild), climbing beans, snow peas, and cucumber varieties trained vertically instead of sprawled.

Train the main stem up your support as soon as it's long enough to loop, tying loosely with soft twine rather than wire, which can cut into stems as they thicken. Vertical growing means more of the plant is exposed to wind, so in exposed rooftop or balcony spots, secure the bag itself against tipping — a full Vertical bag with a mature passion fruit vine carries real weight up top.

ProSoil blends composted organic matter, a coarse aeration component, and a moisture-retentive fraction, mixed to a pH that sits comfortably neutral for the widest range of vegetables and herbs — you don't need to test or amend it before your first planting. It arrives loose and ready to scoop straight from the bag, not compacted, so a little goes further by volume than it looks.

Because it's pre-mixed, ProSoil behaves consistently from bag to bag, which matters more than it sounds — garden soil varies wildly plot to plot, and that inconsistency is one of the most common reasons container growing frustrates first-timers. What works in one ProSoil-filled GrowBag will work the same way in the next.

Fill loosely rather than packing ProSoil down — compaction is the enemy of the sub-irrigation system, since it stops the wicking layer from drawing moisture evenly upward. Fill to roughly 2cm below the bag's rim, leaving a small lip that keeps water and mulch from spilling over the edge when you top-dress or water from above during germination.

• One 25kg bag fills roughly one Standard GrowBag, or two to three Mini bags, or a top-up for a Large bag that's already partially filled from a previous season.
• Water the bag through once from the surface after filling, before planting, so the medium settles and you can see if it needs topping up before seeds or seedlings go in.
• Fill the HydraCore reservoir at the same time you fill the bag with soil — planting into a dry reservoir means the first week of growth relies entirely on surface watering.

ProSoil comes with enough nutrient charge to carry most crops through their first six to eight weeks without any additional feeding. After that, what you do depends on what you're growing:

A diluted organic liquid feed or well-made compost tea is enough for most home growers — there's no need to reach for synthetic fertiliser in a container this size. Over-feeding shows up as lush leaves and poor fruiting, which is a more common mistake than under-feeding.

You don't need to empty and replace ProSoil after every crop. After harvest, remove old roots and stems, break up any compacted patches with your hand or a small trowel, and mix in a couple of handfuls of fresh compost or a top-up of ProSoil to restore volume that's settled or been used up by the previous crop.

A full replace is worth doing roughly once a year for continuously cropped bags, or sooner if you've had a plant affected by disease — in that case, discard the old medium away from other beds rather than composting it, since some soil-borne issues can survive composting at a small-batch, low-heat scale.

ProSoil's fine, even texture makes it usable for direct seed starting without a separate seed-raising mix, which simplifies things considerably for a first GrowBag. Keep the surface consistently moist — not wet — until germination, checking daily rather than relying on the reservoir alone in the first week, since young roots haven't reached down to the wicking layer yet.

For crops usually raised in a nursery bed and transplanted, like tomatoes and capsicum, you can still start them in a small Mini bag or seed tray and move seedlings into their final GrowBag once they have three to four true leaves and a stem sturdy enough to handle without snapping.