Tray Method vs. Top Watering
Both camps have thriving plants. Both camps have confident opinions. Here’s how to actually decide which method is right for what you’re growing.
If you’ve spent any time in carnivorous plant forums, you’ve almost certainly seen this debate play out. Someone posts a photo of a struggling Sarracenia, and within minutes, there are two camps in the comments: the tray method devotees insisting standing water is the only way, and the top-waterers convinced that constantly wet roots are the root of all evil. Both sides are confident. Both sides have thriving plants. So who’s right? The honest answer is that it depends on what you’re growing.
The basics
Sit your pot in a shallow dish of distilled, RO, or rainwater and keep it topped up so the roots always have access to moisture. Most growers keep depth between 1–3 cm for smaller pots, deeper for larger ones.
Water from above, directly onto the soil, and let the pot drain freely. Depending on your setup and climate, this might mean watering every day in summer or every few days in cooler conditions.
When to use the tray method
For bog-dwelling species, the tray method isn’t just convenient — it mirrors their natural environment. Sarracenia, Venus flytraps, and most temperate Drosera grow in waterlogged, nutrient-poor soils where their roots are almost perpetually saturated. Trying to replicate that with top watering alone is an uphill battle, especially through a hot summer.
The practical advantages are real too. If you’re managing a large collection, checking and refilling trays is far less time-consuming than individually watering every pot. And during peak summer heat, the tray acts as a buffer — even if you miss a day, your plants aren’t stressed. For outdoor bog gardens or large container setups, it’s really the only method that makes logistical sense.
The tray method tends to keep the upper layer of media slightly drier, which can reduce mold and algae growth on the surface — a nice side effect that often goes unmentioned.
When to use top watering
Step away from the bog species, and the calculus shifts considerably. Nepenthes are the obvious example. Most Nepenthes — particularly highland and intermediate species — don’t come from waterlogged bogs. They grow in well-draining, airy soils on slopes and ridges where roots can access moisture but also get airflow between waterings. Sitting these plants in a tray of standing water is one of the fastest ways to invite root rot.
Top watering lets you control the dry-down cycle, which matters a lot for these plants. Water thoroughly, let the media approach (but not reach) dryness, then water again. It takes more attention, but the plants respond well.
There’s also a practical benefit worth noting: top watering periodically flushes the media. Over time, even pure water deposits small amounts of minerals, and a good top-watering session helps push those accumulations down and out through the drainage holes. Plants sitting permanently in trays don’t get that flush.
Closed terrariums and high-humidity setups are another case where standing water in a tray can quickly become stagnant and problematic. Top watering gives you more control over moisture levels in enclosed environments.
Common mistakes on both sides
Tray method pitfalls
The most common mistake is keeping the tray too deep for small or young plants. A seedling or recently divided offset sitting in 4 cm of water is under a lot of hydraulic pressure. Keep trays shallow for smaller pots and increase depth as the plant establishes.
Never top off trays with tap water. Even a small amount added regularly will accumulate minerals fast and undermine the whole point of using pure water in the first place.
Top watering pitfalls
The main pitfall is inconsistency. If you’re letting media dry out completely and brick up between waterings, roots are suffering even if the plant looks okay on the surface. The other mistake is watering too shallowly — a quick sprinkle that wets only the top centimetre of media isn’t doing much. Water slowly and thoroughly until it drains out the bottom.
Quick reference
| Plant | Recommended method |
|---|---|
| Sarracenia | Tray |
| Venus flytrap | Tray |
| Temperate Drosera | Tray |
| Tropical Drosera | Either |
| Nepenthes | Top water |
| Heliamphora | Top water |
| Pinguicula | Top water |
| Utricularia (aquatic) | Tray / submerged |
| Utricularia (terrestrial) | Either |
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