Why You Should Never Use Sawdust To Mulch Your Crops

Mulching, especially when growing fruit trees, is one of the most important practises. Commonly, we use dry organic matter such as leaves and grass. One would therefore think that it is also good to use sawdust. However, using sawdust as mulch for plants is generally not advisable for several reasons:

Mulching with sawdust is not recommended

1. Nitrogen depletion: Sawdust is high in carbon and low in nitrogen. When sawdust is used as mulch, it uses up nitrogen as it slowly decomposes. This deprives your plants of the much needed nitrogen. You will notice your plants get stunted and start turning yellow due to nitrogen deficiency. 
2. Acidification of the soil: As sawdust breaks down, it releases organic acids, lowering the pH of your soils below the recommended levels. Most plants prefer a slightly acidic or neutral pH range.
3. Compaction leading to poor soil drainage: Sawdust tends to get compressed easily forming a dense mulch layer that prevents water penetration and air circulation in the soil. If you turn a hip of sawdust after the rains, you will be surprised to find that the lower layers are still completely dry. That is exactly what happens when you mulch with sawdust of wood chippings. Your soils will most often not get water and air circulation beneath the mulch will be very poor. This in turn inhibits the nutrient uptake by your plants. 
4. Disease causing organisms: Sawdust mulch can provide conducive environment for the growth and multiplication of disease causing organisms such as fungus. The acidity caused by the decomposing sawdust can also kill beneficial soil microbes that the plant needs for healthy growth. 
5. Attracting termites: Finally, the smell of dry wood will be a loud invitation to the destructive termites we all fear. The dry conditions underneath the sawdust is a haven for termite activity. If you have planted fruit trees, this will be the start of trouble with these sharp-clawed insects. 

However, note that mixed with other organic materials in a small ration, sawdust can be an excellent mulch. A thin layer of sawdust sprinkled over the soil surface of strawberry farm would also help keep away slugs that love to munch into the berries.