Why Don't My Radishes Form Bulbs? (2024)

Do you have a problem with radishes not growing bulbs? This is a common issue in a vegetable garden. What causes this to happen?

Radishes – raphanus sativus – have edible greens which can be used in salads, but the main reason they are grown is for their crunchy and spicy round root. Expecting to pull out these roots only to discover that you have just a handful of greens and long and thin radishes is a big disappointment.

The good news is that radishes grow very quickly, – often in just 20 days – so once you know the reason for radishes not bulbing, you have lots of time to try again with a new crop.

Keep reading to learn the reasons radishes don’t develop as well as how to fix other radish growing problems.

Why are my radishes not growing bulbs?

This can happen for several reasons and some of the causes are easily fixed. In fact, many of the reasons are self inflicted by not avoiding the common vegetable gardening mistake of not thinning seedlings!

Sowing radish seeds too thickly and soil problems

Radish seeds are tiny and it is easy to sow them much too closely together. This makes it hard for the radishes to form bulbs.

Radishes need plenty of room for their roots to develop into those desirable round shapes. Without this room, they either won’t develop or will form long and thin shapes.

To sow radish seeds properly, plant them 1/4 to 1/2 inches deep in very loose soil and take care not to crowd the seeds. If the soil is too compacted, the bulbs will have problems forming.

If you grow radishes in areas with lots of rainfall in the spring, the soil may get heavy and waterlogged which can make the plant stop producing bulbs.

Also take care not to add too much nitrogen to the soil, since this will promote leafy tops instead of bulbs.

Soil pH can be another reason for a lack of bulbs. Radishes like a soil pH of 6.0 to 7.0. Too alkaline a soil may result in no bulbs forming.

Radishes not thinned properly

Even if you take care when planting the radishes, you may find that they are still growing very closely together once they start maturing. This is where thinning radishes comes into play.

Once the tops have started growing, thin the seedlings so that there is 1 inch between each plant (even more if your varietal has very large bulbs.)

Radishes that are not thinned properly will rub against each other in the soil as they try to grow. This causes the problem of bulbs not forming.

Thin out radish plants when their first true leaves form. To limit any damage to the roots, thin the plant by snipping off the top at soil level. Never try to thin them by pulling the plant out.

Seedlings planted close together can have roots growing together too. If you pull out a nearby plant, you may damage the taproot of the seedlings you want to keep.

H0t weather can cause radishes to bolt and not form bulbs

If you try to grow radishes in hot weather, the plant will bolt and try to set seed instead of forming bulbs.

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The perfect radish is round and plump. What causes radishes to split? The cause is usually a problem with watering. Radishes like consistent moisture – about an inch of water each week is ideal.

Leaving them without water for a week and then adding a lot at one time can cause the root to grow too quickly and split open.

While cracked radishes may not look too appetizing, they are still fine to eat. Slice them and no one will even notice that they were once split!