Sulfur for tomatoes: when to apply

Sulfur is an essential nutritional element for most plants and also for tomatoes. However, sulfur for tomatoes has historically been linked to the prevention of common diseases such as powdery mildew and summer pests such as red spider.

In this article, we offer some recommendations for the correct use of sulfur in the tomato plant. How to apply, when and the recommended quantity to carry out a good preventive action against the main tomato problems.

How to Apply Sulfur to Tomatoes

Sulfur is usually applied to tomatoes as a dusting, using an insoluble powder or wettable powder, spread liberally over all the leaves until a yellow layer forms on the cuticle.

This technique is common among older horticulturists, those who want to see the leaf stained with yellow powder.

Gradually, this sulfur was replaced by wettable sulfurmuch easier to apply, without generating dust that one can inhale and get drunk and with less risk of phytotoxicity due to high temperatures.

The ideal way to apply sulfur to tomatoes is to coat the leaves with powder or apply the soluble sulfur to the leaves, covering them well.

With leaf cover, where the spider mite usually attacks or powdery mildew spots form (conditions of 20-25º C and 50-70% relative humidity)

types of sulfur

  • Sulfur 98.5%. DP (sprinkle with powder): the most common sulfur among older horticulturists, as they want to see the leaves covered with this yellowish powder. A recommended dose of 25-30 kg/ha of tomato (2.5-3 kg/1000 m2 of plantation) or 5-6 grams of sulfur per plant is used.
  • Sulfur 80% WG (wettable powder): widely used in tomato cultivation, it is recommended to apply a dose of 200-500 g/hl (100 L of water) to combat powdery mildew, powdery mildew, red spider and other mites.
  • Sulfur 72% w/v SC (concentrated suspension): the versatility offered by a liquid suspension without generating dust. Effective for the prevention and control of powdery mildew, powdery mildew, red spider mites and other mites, used at a dose of 200-600 cc/hl (100 L of water).
  • Sulfur + copper: when we also look for the added value of the source of copper for the prevention and control of other diseases such as mold or bacteriosis, among others. Recommended dose of Dose: 200-450 cc/hl (100 L of water).

Soluble sulfur for tomato plants

Soluble sulfur is a much simpler and more convenient way to apply, as it is 100% water soluble and this greatly facilitates application by spray or treatment backpack.

We’re not going to see a yellow layer on the sheet like with powdered sulfur, but we’re going to have a high concentration of this element in the leaves and it will act, in the same way, preventing the appearance of diseases such as powdery mildew or parasites such as red spider mites and other mites.

When to Apply Sulfur for Tomatoes

The usual summer tomato plant in early spring, reaping fruit all summer long. For him, before the appearance of the first bouquet It is customary to apply sulfur in the tomato plant.

  • Prevention of mites (red spider): all summer and especially in dry periods without humidity.
  • Prevention of powdery mildew: apply in early spring, as the disease appears at a temperature of 20-25º C and a relative humidity of 50-70%

If used in powder form, the layer of sulfur created will reduce the photosynthetic ability of the plant and may reduce its growth, which is why soluble sulfur is more recommended for the early stages of development.

Does not exist incompatibility in the application of sulfur on a plant with already put tomatoes, but the fruits should be washed well after harvesting.

Remember that for sulfur to have a preventive and curative activity on the leaves, it must be applied foliarly directly to the foliage of the tomato plant.

Frequency of application of sulfur for tomatoes

In case we apply powdered sulfurwe will only reapply when there are no more streaks on the leaf or after it has rained and washed the leaves.

In the case of soluble sulfur for tomatoes, one can apply every 2 weeks, taking into account that it should not be sprayed on the tomato plant at times of greatest heat or wind.

Application Tips

  • not recommended apply sulfur with temperatures above 28 ºC or with high sun exposure, as there may be a risk of phytotoxicity and leaf burn.
  • Wash fruits well after harvesting to remove traces of powdered sulfur that remain on the tomato skin.
  • Wait 20 days from application of sulfur and other oil-based foliar products.

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