Deficiency Disease in Tomato Plants

A healthy tomato plant

Many growers have problems with deficiency "diseases" in their tomato plants. Not true diseases at all, these deficiencies are merely a lack of one or more vital nutrients or minerals. While many different deficiency disorders affect tomatoes, all are easily treatable and, if caught early, the plants usually recover well. Some deficiency disorders, however, do not manifest themselves until the fruit begins to ripen, so it is best to take steps to ensure your tomatoes never experience these problems. The resources section includes a link to a site with pictures of plants with common deficiencies.

Nitrogen Deficiency

Nitrogen deficiency causes plants to grow slowly and thinly. Leaf production will be sparse and what leaves there are will be stunted. A purplish tint may be present. Older leaves will yellow. Note that some tomato varieties exhibit purplish tints naturally in healthy plants. This deficiency is easily treated with fertilizer with a nitrogen component.

Calcium Deficiency

A calcium deficiency can manifest itself in several ways. It can cause the growing tips of stems to die and the stem to die back from the stem tip. It can cause leaves to die, usually beginning with those at the ends of branches. Some leaves may get a brown or purplish-brown stain. Flowers may also be affected. Calcium deficiency can also affect ripening fruit with blossom end rot. This is exhibited as a rotting spot on the bottom of the tomato. Calcium deficiencies are best prevented by adding lime to the soil prior to planting. Little can be done to help the plant once a calcium deficiency is diagnosed.

Phosphorous Deficiency

A phosphorous deficiency is evidenced by dwarfed and very thin growth, with leaves curling and drooping. Leaves may also show a dark purple tint. Phosphorous deficiencies can be prevented by adequate fertilizing with any common garden fertilizer.

Magnesium Deficiency

A plant with a magnesium deficiency will have leaves that are yellowing, but not the veins, which will stay green. Fruit will not ripen properly, staying green at the top where the stem joins. Treatment for a magnesium deficiency is easiest with a weak solution of epsom salts--about one ounce of salts to a gallon of water.

Potassium Deficiency

Tomatoes with potassium deficiencies will show leaves that yellow but retain green veins, much like magnesium deficiency. However, the leaf margins or edges will brown and curl. Fruit will not ripen properly, showing a blotchy, uneven ripening with green and/or yellow spots that seem to ripen slower than the rest of the tomato. Potassium deficiency can be treated with any basic garden fertilizer.

PH

The pH of the soil is an important aspect of tomato cultivation. Tomatoes prefer a pH of between 6.2 and 6.8. A pH too far out of this range will prevent the tomato from absorbing nutrients and minerals from the soil, even if present in quantities normally sufficient for proper growth.

References

• Deficiency diseases in tomatoes
• Tomato soil PH
• treating magnesium deficiency
• treating deficiencies

Resources

• Pictures of deficiencies