PON: What It Is and Why Plant Lovers Are Obsessed With It

If you've spent any time in the tropical plant community online, you've probably seen the word "PON" come up in conversations about semi-hydro growing. It's become one of the most talked-about substrates in the hobby — and for good reason. Here's a complete guide to what PON is, how it works, and whether it's right for your plants.

What Is PON?

PON is a proprietary semi-hydroponic substrate produced by the German company Lechuza, best known for their self-watering planters. The name "PON" is simply Lechuza's brand name for their mineral substrate — it doesn't stand for anything specific.

PON is a blend of three inorganic mineral components:

• Zeolite: A porous mineral with exceptional cation exchange capacity (CEC) — it captures, stores, and slowly releases nutrients, acting as a natural nutrient buffer.
• Pumice: A porous volcanic rock that provides drainage, aeration, and slight moisture buffering.
• Lava rock: A porous volcanic rock that provides drainage, aeration, and an excellent surface for beneficial microbial colonization.

The result is a 100% inorganic, mineral-based substrate with no organic matter, no decomposition, and no soil. It's designed specifically for use with Lechuza's self-watering planter system but has been widely adopted by the broader plant community for semi-hydro growing in any passive reservoir setup.

How Does PON Work?

PON works through the same passive capillary action as LECA — but with some important differences:

• Capillary action: The porous particles of PON absorb water and wick it upward from a reservoir at the bottom of the pot, delivering consistent moisture to roots without waterlogging.
• Nutrient buffering (zeolite): The zeolite component captures nutrients from the water/fertilizer solution and releases them slowly to plant roots. This prevents nutrient spikes and deficiencies, and reduces the risk of over-fertilization.
• Drainage and aeration (pumice + lava rock): The pumice and lava rock components maintain large, stable air pockets between particles, ensuring roots always have access to oxygen.
• Microbial habitat (lava rock): The rough surface of lava rock particles provides an excellent habitat for beneficial soil microbes, supporting a healthy root ecosystem.

PON vs. LECA: What's the Difference?

The key practical difference is nutrient buffering: PON's zeolite component captures and slowly releases nutrients, making it more forgiving with fertilization than LECA. Plants in PON are less susceptible to nutrient spikes and salt buildup, which makes it particularly appealing for growers who want a lower-maintenance semi-hydro system.

How to Use PON

With Lechuza Self-Watering Planters

PON is designed for use with Lechuza's integrated self-watering planter system, which includes a water reservoir at the base and a water level indicator. Simply pot the plant in PON, fill the reservoir with water (and diluted fertilizer), and allow the PON to wick moisture up to the roots. Refill when the reservoir is empty.

In a DIY Semi-Hydro Setup

PON works equally well in any passive reservoir setup:

1. Use a nursery pot with drainage holes placed inside a cachepot (no holes) that acts as the reservoir.
2. Pre-rinse PON thoroughly to remove dust.
3. Pot the plant in PON, ensuring roots are surrounded but not buried too deeply.
4. Fill the cachepot with diluted nutrient solution to 1–2 inches below the bottom of the nursery pot.
5. Allow the reservoir to empty completely before refilling — this prevents root rot and encourages downward root growth.
6. Flush with plain water every 4–6 weeks to prevent salt buildup.

Which Plants Thrive in PON?

Most tropical houseplants adapt well to PON, including:

• Aroids: Monsteras, Philodendrons, Pothos, Scindapsus, and Anthuriums are among the most popular PON plants.
• Hoyas: Thrive in PON's open, airy structure.
• Orchids: Epiphytic orchids adapt well to PON's drainage and aeration.
• Syngoniums and Aglaonemas: Fast-growing tropicals that transition to PON readily.
• Peace Lilies and ZZ Plants: Both adapt well to semi-hydro conditions.

Fertilizing in PON

Because PON is inorganic and contains no nutrients, all nutrition must come from the water/fertilizer solution. Use a balanced hydroponic nutrient solution at half strength. PON's zeolite component buffers nutrients, so you have more flexibility than with LECA — but regular fertilization is still essential. Flush periodically to prevent salt accumulation.

Is PON Worth It?

PON is more expensive than LECA and less widely available, but its nutrient-buffering properties and microbial-friendly composition make it a genuinely superior semi-hydro substrate for many growers. If you're already using Lechuza planters or want a more forgiving semi-hydro system than LECA, PON is an excellent choice.

For growers on a budget or those who prefer to DIY, a blend of zeolite, pumice, and lava rock in roughly equal proportions can replicate PON's properties at a lower cost — and many experienced semi-hydro growers do exactly this.