Radishes will grow above ground if the seeds are planted too shallow, if the soil has been washed away from the roots through heavy watering, or if the soil is too high in clay and hard. Radishes that do not have enough space to grow will push the surrounding plants out above the ground.
This article will explore some easy tips to stop your radishes from pushing above the ground. This will help to give you large, delicious and crispy radishes for salads at home.
The ideal depth for radish growth is to have the top ¼ of the radish above ground. As the radish grows larger you will start to see the top red root pop above when it is getting close to ready to pick.
6 Tips to stop radishes growing above the ground
Here are some easy tips to follow to stop radishes from growing above the ground, drying out and tasting bitter.
1. Plant seeds ½ to 1 inch below the soil
Radish seeds that are planted too shallow will start to grow above the ground as they get larger. It is important to plant them deep enough to stop the roots from popping up above the surface of the soil.
2. Water seeds and seedlings gently
Watering radish plants and seeds with a water pressure that is too direct or high can wash soil away from the roots and cause them to pop above the ground.
To avoid this I like to water radish seeds with a light mist setting on my hose sprayer nozzle. I often also use a sprayer bottle to gently water seeds.
Once the radish plants have grown bigger you can switch to a watering can with a rose attachment or keep watering with your hose on the shower setting.
Water radish plants every 2-3 days to keep them moist once the seed have established.
For more on how to water radish plants, check out my article here: How Much Water do Radishes Need? | A Simple Guide
3. Regular water
Radishes that are allowed to dry out can grow and pop up above the ground. Dry and crumbly soil can be blown or washed away from the root zone easily leaving the radish tuber exposed.
Water radish plants 3 times per week to stop the soil from drying out and crumbling away. Place a light layer of straw mulch around mature radish plants to keep the water in the oil for longer.
4. Thin radish seedlings out to 2 inches apart
If radishes are grown too close together they will push each other out above the ground. Thinning seedlings is important, leaving a 2 inch gap between each plant. This will allow the space the radishes need to grow large while still staying under the surface of the soil.
5. Plant radish seeds when the weather is mild
Planting radish seeds when the weather is too hot can lead to hard, dry and bitter radishes. They are more likely to pop up above the ground as the soil can dry out quickly and crumble away.
Aim to plant radishes in the mild weather months of spring and fall. When the weather is too hot the soil can dry out quickly and the radish can turn tough, and it can taste hot or bitter.
6. Plant radishes in soft and friable soil
Planting radishes in compact soil that is too high in clay can force them to pop above the soil surface.
Before planting radish seeds dig the soil over thoroughly with a fork to loosen it. Add compost and aged cow manure through the soil to add organic matter with minimal fertilizer.
Radishes do not need loads of nutrients but grow best in soil that is light and airy. This will allow the roots to grow down, rather than popping up above the surface of the soil.
Why are my radishes all tops and no bottom?
Another common problem with radishes is that they can grow load of leaves and no bottom or roots. This is caused when the soil is too high in nitrogen. This causes lots of leaf growth but minimal root growth and smaller radishes.
To avoid this, rotate your crops from season to season. Plant radish seeds in a garden bed after growing nitrogen hungry plants like leafy greens. This will mean that the soil is lower in nitrogen and your radishes will not overgrow their leaves compared to roots.
Do not add any nitrogen based fertilizer to the soil before planting radishes. Avoid mixing pelleted chicken manure or any synthetic nitrogen fertilizers to the soil.
Check out this video for more.
How do you know when radishes are ready to harvest?
Radishes are ready to harvest when the roots have reached the size you are aiming for. I like to pick my radishes early as they are milder in taste and not as hot.
I like to look out for the tops of the radish to start poking above the soil. This usually takes around 4 weeks. Pull out 1 of the radishes to see how big it is. Radishes planted at the same time with the same space to grow will be a similar size.
If you want larger radishes, water them well and leave the in the soil for another week.
Why are My Radishes Growing Above Ground? | Summary
Radishes will grow above ground if the soil is too hard, if they are not watered enough or if the seeds are planted too shallow. Mix the soil thoroughly before planting radish seeds to allow the roots to grow deeper into the soil. This will help to stop the roots from popping above the ground.
I am an accredited practicing dietitian, experienced gardener and a dedicated cook. I love writing and sharing my experience so you can learn from my successes and mistakes.