What Kind of Mulch Is Best for Lemons?

Soil Conditions

• Besides proper climate and lots of sunshine, the most important aspect to growing a healthy lemon tree is appropriate soil conditions. A fertile soil is a necessity, either naturally or by the use of fertilizers. Lemon trees do not tolerate soils that drain slowly. A sandy to loamy soil is best, as it ensures the ground never floods after rains. An acidic soil also is needed to prevent nutrient deficiencies, most often seen as yellowing leaves.

Mulch Concerns

• Placing a layer of mulch over the soil under and around a lemon tree creates potential problems. Organic mulch, such as bark nuggets or compost, slows the drying of the soil surface after irrigation or rain, potentially increasing habitat for fungal diseases to proliferate. Slow-to-dry soil under the lemon tree also can cause roots to rot. Although an evenly moist soil in summer is beneficial, the mulch prevents timely drying of the soil. Adding organic mulch to the citrus orchard also can introduce various insect pest eggs or spores of fungi into a moist, warm soil environment.

Inorganic Mulch

• Even inorganic, sterile mulches, such as pebbles, rubber bits or layers of nylon or plastic fabric, do not create a better situation compared to organic mulches. While disease introduction and pest threats are low, the mulch still slows the drainage and drying of the soil under the lemon tree. Moreover, rock and plastics -- especially if dark colored -- heat up more quickly. Warmer soil and adjacent air temperatures experienced by the lemon tree increases its need for soil moisture. Excessive heat may also cause scalding of leaves, flowers or fruits.

Recommendations

• Do not lay any mulch under the boughs of a lemon tree. Instead, leave bare soil from the trunk outward to the dripline, the farthest reach of the branch tips where rainfall falls directly on the soil. If mulch is laid, use a coarse-textured, acid-forming material such as large pine bark nuggets. Maintain a layer only 2 inches deep, and certainly never closer than 12 inches from the lemon's trunk. Err on the side of caution, however, because once a lemon tree contracts a fungal infection or root rot from overly wet soil conditions, the prospect for complete cure is dim. Hand weed or shallowly hoe under the lemon tree to keep the bare soil looking neat.