Drainage
Quick answer. Roots need air as well as water. Waterlogged soil has its air spaces filled, roots cannot function, and the plant wilts — which looks identical to drought and is commonly treated with more water. Check the soil before adding any. In a hot dry country the assumption is always that a wilting plant is dry, and that assumption kills plants.
What waterlogging does
Two things at once. Physically, it excludes air from the root zone, and roots deprived of oxygen stop taking up water — which is why the plant wilts despite standing in wet soil. Chemically, it changes what happens to nutrients: FAO records that waterlogging causes loss of nitrogen through denitrification of nitrate, and that in waterlogged soils the concentrations of ammonium ions, phosphorus and iron change relative to aerated conditions.
So a waterlogged bed is simultaneously suffocating its roots and losing the nitrogen you applied.
Where the risk actually is
FAO notes that as free-draining soils become waterlogged less readily, the risk is greatest on high-clay fine-textured soils. On a sandy Kuwaiti soil the everyday risk is lower — sandy soils provide favourable drainage of surplus water, as FAO puts it.
But three local situations override that. A hardened lime crust in the subsoil — which FAO names among arid-soil problems — turns a hole dug down to it into a basin. A container without a functioning drainage hole is a closed vessel. And a compacted layer, whether from construction, machinery or foot traffic, does the same thing on a larger scale. In all three the surface soil can be sandy and free-draining while the root zone sits in standing water.
How to check
Dig and look, before planting rather than after. A hole that holds water for a long period after filling is telling you there is an impermeable layer, and the planting decision should change in response — break through the layer, plant higher, or choose another position. This is far easier before a tree is in the ground than after.
The two-way diagnosis
Wilting means the plant is not moving water. Dry soil and waterlogged soil both cause it. The only reliable way to tell them apart is to check the soil at root depth, not at the surface, and a plant that wilts at midday and recovers in the evening may be doing neither — that is a heat response, where transpiration temporarily outpaces uptake in a plant with adequate water.
Never respond to wilting by watering without checking. If the cause is waterlogging, the remedy accelerates the damage, and the plant's decline appears to confirm that it needed even more water. Check at root depth first. A visual symptom alone is not a confirmed diagnosis.
Sources
FAO — Fertilizer and Plant Nutrition Bulletin 16, Chapter 7 (waterlogging, denitrification and nutrient availability), Chapter 4 (texture, aeration and drainage), Chapter 5 (arid soils: lime crusts and usable profile depth). Accessed 27 August 2026. No quantity or interval is stated.
Last reviewed 27 August 2026