Why Are Black Seeds In My Tomato?

black seeds in tomato

Black seeds in tomatoes have been a source of worry and headache for many gardeners who know how susceptible to disease the plant can be.

The usual response by most consumers seeing black seeds in tomatoes is, to cut out the area around the black seed and throw it away. As it turns out, these seeds are quite harmless if all else seems alright with the tomatoes themselves. Black seeds usually occasionally appear as tomato seeds range from greenish to yellow and sometimes take on darker shades from brown to black.

However, it is worth noting that dark seeds in tomatoes and characteristics defects like decay, foul odors, and the like could be a sign that something is very wrong with the plant.

Over Ripened Tomatoes:

Black seeds are often a sign of vivipary.

When tomato seeds turn black, they are usually a sign that the tomatoes are long over-ripe and the seeds are due for planting and germination. Abandoning the tomato any longer and these black seeds would begin to grow and sprout cotyledons inside the tomato fruit, this process is called vivipary. Before vivipary occurs, the tomato may be consumed safely, but once the seeds start sprouting, it may be best to consider replanting rather than consumption.

Blossom End Rot (BER):

BER is one plant disease very common to tomatoes and a good number of fruit-bearing plants.

It occurs due to the plant’s failure to perform the impossible task of absorbing calcium from the soil at a rate fast enough to keep up with the accelerated growth speed brought about by fertilizers or an irregular watering cycle. You can easily notice Blossom End Rot on a plant by the rotting/discolored base of its fruits while other parts are either ripe or at certain times, unripe.

Fortunately, BER does not mean complete waste in tomatoes as the discolored part can be safely cut and discarded while the rest is consumed safely. Since Blossom End Rot is a calcium deficiency, it can be prevented by;

  • Mulching the soil to prevent it from drying out and providing much-needed moisture to the roots
  • Using Calcium rich nutrients and fertilizers
  • Practicing a regular watering system
  • Watering the tomato plant at its roots not stems or leaves.

Tomatoes Picked Too Early (Unripe Tomatoes):

Ever cut open an unripe tomato?

Or plucked one early and left it to ripen by itself indoors?

In either case, the tomato fruit would have many seeds of darker coloration than the usual green. The reason for this is the sudden drop in the Abscisic acid supplied to the tomato as it has been detached from the plant for a while. The dark seeds in tomatoes are just an end product of tomato ripening away from its roots and can be eaten without any worries.

Other Possible Causes:

Genetic Variation

Certain color changes in seeds from green to black may not be a result of any particular defect or illness in the plant. For reasons unknown, some plants mutate from their parent gene and have naturally black seeds now and then.

Breed

Some breeds of tomatoes like the Indigo Rose breed have naturally black seeds inside tomato. With many breeds of tomatoes available, it should not be a surprise if a breed has been crossbred with another, resulting in black seeds upon harvest.

More on Blossom End Rot

Most times, the black coloration of the seeds, base, and insides of the tomato plant is a case of Blossom End Rot. Fortunately, this does not mean the end of the plant as the calcium deficiency can be readily rectified and the plant restored. As soon as BER is observed in a plant, it should be treated immediately, as the deficiency can present itself in nearby fruit-bearing crops close to the affected plant.

Causes of Blossom End Rot (BER):

Blossom End Rot is not a disease but one of many results of a deficiency in a plant’s growth cycle. There are two notable causes of BER mentioned earlier in this article; let us take a more in-depth look at these causes:

  • Irregular Watering:

Watering tomato plants correctly could be something of a precarious affair; too much water and the plants would literarily drown; too little and the plant is stressed, making it susceptible to a host of diseases and deficiencies waiting to set in; watering just right but at irregular intervals and you will have a case of Blossom End Rot on your hands.

Overwatering the tomato plant drowns the roots and causes the soil moisture to fluctuate beyond the plant’s tolerance levels, making absorbing calcium and other soil-present nutrients difficult.

  • Calcium Deficiency:

The inability of the plant to absorb calcium for any reason results in Blossom End Rot.

This could be brought about by fluctuating soil moisture, unsuitable soil for thecalcium-deficientm deficient fertilizers, and any action that reduces the amounts of calcium available to the plant.

Preventing Blossom End Rot

Blossom End Rot is usually caused by soil dryness and fluctuating soil moisture levels; knowing this, preventing BER becomes easy as all one has to do is:

  1. Keep Plants well-watered:

Make sure the roots of your tomato plant are properly watered with about an inch of water from a watering can daily. Please do not make the error of spraying water at the leaves and stems; instead, aim for the roots and spray water at them. Keeping the leaves dry as much as possible will help prevent diseases.

  1. Add Mulch:

Organic mulch, specifically of about 2-inch should be placed around the base of the plants to provide them with the much-needed calcium and other nutrients.

For organic mulch, use a material like straw, grass clippings, chopped leaves, or shredded bark; this help maintain the soil moisture at a constant level so the tomato plant does not dry out before the next watering period.

  1. Do not over-fertilize:

Fertilizers cause plants to grow accelerated for a faster harvest; however, these desires for fast growth could be the Achilles heel in a well-maintained tomato plant.

A gardener or farmer who takes the utmost care of his plants, practicing proper watering techniques at the roots at a specific time with a constant amount of water and organic mulch set in place, would ultimately be surprised to find blossom end rot setting in.

In this scenario, the culprit would be his desire for a quick harvest and subsequent application of multiple fertilizers. These fertilizers cause the plant to grow faster than it can absorb calcium and other elements from the soil.

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What to do If your tomato plant develops BER:

Upon noticing BER, the very first thing you should do is reflect on your actions regarding watering and caring for your plant. As discussed here, you may be guilty of one or more causes of Blossom End Rot.

If there are no signs of BER or any unpleasant characteristics in your harvested tomato, yet a few of them have one or two black seeds present, then there is no cause for alarm as the crop is perfectly fine.

Tomatoes may be a delicate plant to cultivate; however, the rewards are worth considering their economic value, abundance upon harvest, and all-year-round yield. Black seeds inside tomato should not keep you from enjoying a plate of raw or well-cooked tomato salad, so go ahead and reap the rewards of your hard work!

Author: Green Thumb Dad

I am a dad, blogger and I love gardening, feel free to read the whole story.

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