Many gardeners think that more is better when it comes to water – but it is possible to give plants too much! An overwatered plant can be just as problematic as an underwatered one. As a guide, water when the soil or potting mix is beginning to feel dry. Check soil before watering, as it may look dry on the surface but contain plenty of moisture just beneath. Use your finger to check moisture conditions in the soil or potting mix before watering.

Plants vary in how often they need watering depending on their growth cycle, the temperature, soil conditions as well as other factors such as wind and the season. Generally, plants need less frequent watering in winter, and more frequent watering in spring and summer when conditions are warm and plants are actively growing.

Hand-in-hand with watering is drainage. Most plants like water to drain through the soil or potting mix so it is accessible to the root system. However, if the soil can’t drain and the root system is inundated with water that doesn’t drain away, then the plant may die. A balance between air and moisture in the soil or potting mix is essential for healthy root growth.

 

Plant looking wilted and floppy? You may have overwatered it.

 

Signs of an overwatered plant

There are clear signs when a plant is getting too much water. Symptoms of an overwatered plant include wilting (even though the soil looks wet) and dieback. Roots may rot away if they remain too wet for too long. The soil or potting mix will feel wet and, if the plant is in a container, it will feel heavy. To help the plant, stop watering and set about improving its drainage.

Once you have improved drainage, trim off any rotted roots and damaged growth and repot. The plant can also be helped by applying Searles Root Rot Systemic Fungicide, available from Flower Power.

 

Water pools on the surface of your potting mix as you water? If it doesn't drain away, that may indicate that your drainage holes are blocked.

 

Fixing an overwatered plant in a pot

Potted plants are the ones most at risk of overwatering. Check there are drainage holes in the pot and that water can drain from them. Drainage holes may become blocked with roots, particularly if the plant has outgrown its pot. Clear blocked drainage holes or repot the plant to fix this drainage problem.

When repotting, always use a good-quality potting mix - Flower Power recommends the Supersoil Professional range. Don’t fill the base of the pot with extra drainage materials such as broken pots or pebbles. These can cause water to stay in the potting mix (known as a perched water table) and make drainage worse!

Where you are concerned about dirt leaking from containers, place a small piece of mesh over the drainage hole so water can still drain but the potting mix can’t.

If there is inadequate drainage in a pot, repot into a container with more drainage holes or, if possible, drill more holes in the base of the pot to assist drainage. If using large containers, elevate them slightly to assist drainage. This can be done by placing them on pot feet (available at Flower Power) or on bricks. As well as assisting drainage, elevating the pot also makes it easier to check that the pot is draining well when you water it.

If a plant is sitting in a cover pot that has no drainage or in a saucer, the simplest fix may be to empty the water that’s accumulated. Provided there are clear drainage holes in the base of the pot, then the water should be able to drain away. Aid drainage by watering an indoor pot plant on a draining board beside the sink or in the laundry. Wait until excess water has drained away before returning the plant to its home.

 

 

Muddy, soggy soil could be an indication that you've overdone the watering.

 

Fixing overwatering in garden beds

Where garden soil is poorly drained and plants are dying in the wet conditions, it is important to improve soil drainage. You may need to remove each overwatered plant and place them into containers while you work on improving the surrounding soil. For large poorly drained areas it may be necessary to install subsurface drains. Surface drains may also be needed to redirect water away from garden beds to avoid overly wet conditions.

Soils that are heavily clay based are likely to be poorly drained. To help improve poorly drained clay soils, work in gypsum (also sold as clay breaker) and organic matter such as compost or manure. To check whether the soil is draining adequately for planting, dig a hole, fill it with water and check how long it takes to drain. If the hole contains water the next day, it is still too poorly drained for planting.

If the soil is still poorly drained, create raised garden beds and plant into those. Even raising the soil level by 30cm can improve growing conditions. Raised garden beds generally have a border or edge to contain extra soil. This can be made using stone, brick, concrete, timber, metal or other form of garden edging.