As a tomato farmer, you know that weed control is a crucial aspect of successful tomato production. Among the various limiting factors that affect the growth of tomatoes, weed competition is a major contributor to yield loss. In fact, research has shown that the critical period during tomato production in which effective weed control is most important is between 12-48 days after transplant. During this time, competition with weeds can result in an 80% decrease in yield. Therefore, it is essential to manage weeds effectively to ensure optimal yields.

Why Weed Control is Important

Weeds compete with tomato plants for essential resources such as nutrients, moisture, and light. They can also harbour pests and diseases that can affect the health and productivity of your plants. In some cases, certain weeds, such as Tall-Khakibush (Tagetes minuta) and Blackjack (Bidens bipinnata), emit allelopathic substances that inhibit the growth of tomatoes. Effective weed control can also ease the process of harvesting and reduce weed pressure on follow-up crops.

Mechanical Control of Weeds

Mechanical weed control involves the use of manual labour and tools such as hoes, spades, and other implements to remove weeds. This method is particularly beneficial for small-scale farming operations that have limited access to specialized equipment. It is important to pay close attention to the 12-48 day period mentioned earlier, and take care not to damage the surface fine root system when hoeing close to the root zone. Damage to the root system can provide an entry point for soil pathogens, which can affect plant growth and yield. In-row weed control can also serve as tillage, which can help the plant form secondary roots and strengthen its structure to prevent wind damage.

Chemical Control of Weeds in Tomato Fields

The use of herbicides is a more expensive option that is usually limited to larger commercial farms. However, it can save considerable time and labour costs. Herbicides can be broadly categorized into pre-emergence and post-emergence varieties. Unfortunately, registered herbicides for tomatoes are limited, with post-emergence herbicides including cetoksidium and cicloxyidim, while pre-emergence herbicides include metribuzin, difenamid, and traufluralin for both grass and broadleaf weeds. It is important to follow the instructions provided on the label carefully and always wear protective clothing when working with harmful chemicals.


Weed control is an important aspect of tomato production that should not be overlooked. Effective weed management can help you to eradicate limiting factors, optimize yield and production, and maintain a healthy balance between cost and profit. Both mechanical and chemical weed control methods can be effective, but it is important to choose the best option for your farming operation. With the right approach, you can successfully manage weeds and ensure a profitable tomato harvest.