Create a water garden: design a garden pond intended for plants, from choosing the location to the first bloom

A water plant pond is not a fish pond with a few iris pots added. It is a garden whose soil is water: you design it so that each plant finds its depth, light, and place. The good news is that it is also the easiest type of pond to maintain, often without a pump or filter. Success depends on the design: a sunny location, a well-planned stepped profile, and a poor substrate do more for success than any piece of equipment.

The location: light above all

Most aquatic plants flower in full sun. A water lily in the shade produces leaves, but rarely flowers. Look for a spot that receives at least five or six hours of direct sunlight in summer, ideally in the morning and early afternoon. Keep away from large trees: their leaves fall into the water in autumn, decompose and feed algae, and their roots make digging more difficult. A low point in the garden may seem logical, but it collects runoff laden with soil and fertilizer: a slightly raised spot or one protected by a small berm is better.

The profile: designing levels for each plant

This is the major difference from a fish pond, which is often deep with steep sides. A plant pond needs wide shelves because each category of plant lives at a specific depth.

Give the slopes a gentle gradient, especially on the marsh side: this is where wildlife enters and leaves the water. The deep zone also serves as a winter refuge: in our climates, a few dozen centimetres of water beneath the ice are enough for hardy plants.

Waterproofing and the edge: the invisible mistake

After digging, remove stones and roots, lay down a protective felt, then the liner, preferably EPDM for its flexibility over irregular shapes. The most commonly neglected point is the edge. If garden soil touches the water over the liner, it acts like a wick and draws water from the pond day after day: this is the classic cause of a pond that “leaks” even though the liner is intact. Raise the liner vertically beneath the edging stones or along a trench to create a capillary barrier.

The substrate: poor is better

Resist the temptation to line the bottom with good garden soil. It clouds the water, releases nutrients for years, and causes algae to explode. Two approaches work. Either use baskets and pockets filled with a specific aquatic potting soil, which keep the bottom clean and allow you to move the plants. Or, for a more natural look, use a layer of washed sand and gravel on the shelves, planting directly into it. Wetzel points out that sediments are the main nutrient reservoir in a body of water: what you put on the bottom determines the water quality for a long time.

Fill and plant

Rainwater is ideal if you can store enough. Tap water is also suitable: it meets the drinking water standards of Directive (EU) 2020/2184, but it may contain nitrates, phosphates, and chlorine; let it stand for a few days before planting. Start with oxygenating plants and marginal plants, which establish quickly, then add water lilies once the water has warmed up. Plant a good portion of the shelves during the first season: new water without plants is an open invitation to algae.

Choose native species or species proven in water gardens, and check that none appears on the European list of invasive alien species under Regulation (EU) 1143/2014.

The first season: patience

Almost all new ponds go through a phase of green water in spring or early summer. This is normal: the nutrients are there, and the plants are not yet developed enough to consume them. Do not empty the pond or use more products. Remove filamentous algae by hand, let the plants grow, and the water generally clears when the vegetation takes over. Scheffer describes this shift toward clear, plant-dominated water, which becomes stable once established. Wildlife arrives on its own: dragonflies, water striders, amphibians. Many of them are predators of mosquito larvae.

Read also

To understand the role of each plant: Why put aquatic plants in a pond?.

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Frequently asked questions

— Does an aquatic plant pond need a pump?

Not necessarily. A well-planted pond with few or no fish often finds its balance without a pump. Some circulation is still useful in summer or for a waterfall.

— How deep should a plant pond be?

Shelves from 0 to 30 cm for marginal plants, and a deep zone of at least 40 to 80 cm for water lilies and overwintering.

— Should I put soil at the bottom of the pond?

No. Use baskets and aquatic soil, or washed sand and gravel; garden soil enriches the water and encourages algae.

— Why is the water in my new pond green?

This is a normal phase of the first season: the plants are not yet consuming enough nutrients. Let them establish themselves.

In summary

• At least half a day of sunlight, away from large trees.
• Wide shelves: marsh, shallow zone, deep zone.
• Raise the liner at the edge to prevent the wick effect.
• Poor substrate, baskets or pockets, never rich soil.
• Plant generously from the start, then be patient.

Last updated: September 29, 2026.