Pond plants for oxygen: July maintenance in the wildlife garden

Key points at a glance

• High water temperatures in July reduce oxygen solubility, which can lead to decay processes.
• Submerged plants are essential as they release dissolved oxygen directly into the water through photosynthesis – the conversion of light energy into chemical energy.
• Avoiding nutrient input prevents algal blooms, which place additional strain on the oxygen balance.

The role of submerged plants in a summer pond

In July, the pond ecosystem reaches a critical phase. As temperatures rise, the water absorbs less oxygen, while the metabolism of pond inhabitants increases due to the heat. True submerged plants, which grow completely underwater, act as biological aerators. They also compete with algae for excess nutrients such as phosphates and nitrates.

Should algae multiply rapidly, the use of mechanical removal methods (such as a pond net) is advisable. Chemical treatments should be strictly avoided, as they permanently disrupt the ecological balance and can harm aquatic insects such as dragonfly larvae (Anisoptera) or backswimmers (Notonecta glauca).

Selection of suitable species for the pond

The following overview shows native species that are particularly valuable for stable oxygen supply and nutrient binding in summer:

Recommended actions for July

1. Stock check: Check whether the submerged plants are receiving enough light. Too many floating-leaf plants (such as water lilies) can suppress the light-dependent oxygen production of the underwater flora through shading.
2. No fertilising: Fertiliser in the pond only promotes algae growth and, when it dies off, leads to oxygen depletion through decomposition processes.
3. Heat management: In extreme heat, slight shading of the pond edge by marginal plants can stabilise the water temperature. Ensure that no nutrient-rich organic matter (such as grass clippings) enters the water.
4. Mechanical maintenance: Carefully remove dead plant parts with a pond net. Otherwise, this biomass would bind oxygen in the water during decomposition and cause the pond environment to crash.

FAQ

• Question: Is a water pump enough to fix an oxygen deficiency? Answer: Pumps move water, but only increase the oxygen content through surface turbulence. Plants are essential for biological oxygen production.
• Question: Why do blanket weed (filamentous algae) form despite having many plants? Answer: Blanket weed takes advantage of an excess of nutrients. Reduce leaf input and avoid fertiliser so that the submerged plants gain the upper hand.
• Question: Can I add more pond plants in July? Answer: Yes, seedlings from the local area can be planted, but they require protection from intense direct sunlight during the establishment phase.

Frequently asked questions

Is a water pump enough to fix an oxygen deficiency?

Pumps move water, but only increase the oxygen content through surface turbulence. Plants are essential for biological oxygen production.

Why do blanket weed (filamentous algae) form despite having many plants?

Blanket weed takes advantage of an excess of nutrients. Reduce leaf input and avoid fertiliser so that the submerged plants gain the upper hand.

Can I add more pond plants in July?

Yes, seedlings from the local area can be planted, but they require protection from intense direct sunlight during the establishment phase.

Main article: Wildlife gardening in July: How to manage succession and pond ecology