Growli

Soil & potting mix

Best soil for Philodendron subhastatum (Philodendron subhastatum)

Also called Subhastatum, Red-Back Philodendron.

More about philodendron subhastatum

About Philodendron subhastatum

Philodendron subhastatum · also called Subhastatum, Red-Back Philodendron · houseplant

Philodendron subhastatum is a striking climbing aroid with large, glossy, arrow-shaped leaves that are deep green above and dramatically flushed red to maroon on the undersides. As it climbs and matures, the leaves enlarge and the bicolour effect intensifies. A vigorous, relatively easy grower, it makes a bold statement on a moss pole in bright, humid conditions.

Preferred mix: Chunky, well-draining aroid mix

Watch for — Yellowing leaves: Overwatering or poor drainage. Let the top third of the mix dry and ensure the pot drains freely.

Why philodendron subhastatum needs this mix

Philodendron subhastatum is a climbing rainforest aroid — it wants a chunky, bark-heavy mix full of air pockets, not a dense soil that packs around its thick roots.

For the full picture on what makes up a good mix, see our guide to the main types of soil and potting media — it explains why each ingredient above behaves the way it does.

What goes wrong with the wrong mix

The wrong soil is one of the most common reasons philodendron subhastatum struggles, and the damage often shows up weeks later as a watering problem. For this species specifically:

Using ordinary potting soil with no bark or perlite. Philodendron subhastatum needs roughly half its volume as chunky, airy material — that single change fixes most "mystery decline".

pH — does it matter for philodendron subhastatum?

Philodendron subhastatum prefers a slightly acidic mix, around pH 5.5-6.5, which a peat-free compost-and-bark blend lands on naturally. It is not fussy enough to need testing in practice.

If you want to check or adjust it, the soil pH guide walks through testing and the safe ways to nudge a mix more acidic or more alkaline.

DIY mix vs a bagged one

Bagged "aroid mix" is now widely sold and is a fine shortcut for philodendron subhastatum, but check it actually contains visible bark and perlite — many are just rebranded compost. Mixing your own from the ratio above guarantees the structure.

Drainage and the pot

Any pot with a drainage hole works because the chunky mix does the draining. A pot only a little larger than the rootball avoids a wet, unused core; add a moss pole and the climbing roots will thank you.

Bark breaks down over time, so refresh the mix for philodendron subhastatum every 12-18 months even if the pot size is still fine — spent, sludgy bark is a common hidden cause of decline. When the time comes, our repotting guide for philodendron subhastatum covers the timing and technique step by step.

Philodendron subhastatum soil — frequently asked questions

What is the best soil mix for philodendron subhastatum?

2 parts peat-free houseplant compost or coco coir : 2 parts orchid bark (fine-medium) : 1 part perlite : 1 part horticultural charcoal. In the wild philodendron subhastatum climbs trees with thick, partly aerial roots that expect air as much as moisture — bark and perlite recreate that open structure.

Can I use normal potting soil for philodendron subhastatum?

Plain bagged compost packs tight around philodendron subhastatum's thick roots, holds water in the centre and triggers the yellow-leaf-then-mushy-stem rot pattern. Bagged "aroid mix" is now widely sold and is a fine shortcut for philodendron subhastatum, but check it actually contains visible bark and perlite — many are just rebranded compost. Mixing your own from the ratio above guarantees the structure.

Does philodendron subhastatum need a special pH?

Philodendron subhastatum prefers a slightly acidic mix, around pH 5.5-6.5, which a peat-free compost-and-bark blend lands on naturally. It is not fussy enough to need testing in practice.

Should I buy a bagged mix or make my own for philodendron subhastatum?

Bagged "aroid mix" is now widely sold and is a fine shortcut for philodendron subhastatum, but check it actually contains visible bark and perlite — many are just rebranded compost. Mixing your own from the ratio above guarantees the structure.

How often should I refresh the soil for philodendron subhastatum?

Bark breaks down over time, so refresh the mix for philodendron subhastatum every 12-18 months even if the pot size is still fine — spent, sludgy bark is a common hidden cause of decline. Any pot with a drainage hole works because the chunky mix does the draining. A pot only a little larger than the rootball avoids a wet, unused core; add a moss pole and the climbing roots will thank you.

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