When it comes to ideal plants for beginning gardeners, radishes are hard to beat. Most varieties are naturally pest resistant, extraordinarily hardy and many of them can grow to full size, ready for harvest in only a month.
That’s pretty awesome, but there are still things that you’ll have to get right if you want your radishes to grow big and tasty in a timely fashion.
Like most plants, that starts with proper sun. How much sun do radishes need daily?
Most radish varieties need around 6 hours of sunlight per day, sometimes more if the weather is cool, and depending on the type. Note that there are some radishes that will grow just fine in the shade.
Radishes aren’t the most popular “salad” vegetable, but we’re seeing something of a comeback with them as more and more people take to starting their own at-home garden.
Whether you want to grow small or large radishes, getting their light requirements right is important for best flavor and overall quality.
I will tell you everything that you need to know in the rest of this article. Grab your trowel and let’s get going!
Is Full Sun Best for Radishes?
Full sun is generally best for radishes, but not necessarily a requirement depending on the variety.
Many do fine with indirect sunlight if they have some overhead cover and can even grow when shaded for most of the day.
How Many Hours of Sun a Day is Best for Radishes?
For most radishes, 6 hours of sunlight daily is all they will need to grow properly and produce a tasty, peppery vegetable.
Will Too Much Sun Hurt Radishes?
Radishes can get too much sun if the weather is very warm, or if the root is exposed above the level of the soil.
In this case, the root can get scalded or the whole plant may go to seed and flower. If that happens, you might be able to stop the process, but chances are the quality of your future radishes will greatly diminish.
Going to seed, also called bolting, can occur due to a variety of stressors, not just too much sunlight.
Basically the plant, sensing that its existence might be in danger, will stop funneling resources into the fruit (or in this case the root), and will try to reproduce by flowering as quickly as it can.
This takes a lot of resources and will deprive other parts of the plant, specifically the part we want to eat!
If you catch a radish plant going to seed early enough, it is possible to slow it down and potentially salvage it if you shade it and take care of any other problems concerning its care.
Make sure to also check soil nutrient levels, moisture levels, and also check for pests (though this latter cause is unlikely since radishes are naturally pest resistant).
Do Radishes Do Well in Indirect Sun?
Yes, most do, and certain varieties can do wonderfully with indirect sun whether you have an overhead canopy or other shade outside, or you’re just trying to get them started or even grow them indoors.
Some cultivars that do especially well with indirect light include the Scarlet Globe and Cherry Belle.
If you do decide to try them indoors, all you need to do is set them up near the sunniest window in your home, usually one that is facing south, and make sure they get plenty of light for around 7 hours.
Alternatively, they‘ll do just fine using grow lights, so you should take care to ensure that the tops of the roots are below the soil at all times.
Will Radishes Thrive in Shade?
Yes, many can do quite well in shade. Radishes generally do better when they are cool, and they also need cool soil.
Shade can help keep the plant cool both above and below ground, keeping your radishes happy and growing quickly.
When planting radishes, don’t hesitate to plant them in an area in or around your garden that gets some shade throughout the day.
As long as they get around 6 hours of sunlight they should do fine, and you can get varieties that can grow well even in deep shade.
What Happens to Radishes That Don’t Get Enough Sun?
Radishes don’t need nearly as much sun as other vegetables, but they still need their fair share and if they don’t get it they will go “leggy” by growing more and longer leaves on top of the root.
They do this in an effort to reach past any obstructions to get more of the light that they need.
When your radishes go leggy they are still salvageable if you can relocate them or otherwise provide them with more light, but at this point the root will be growing much slower than it would otherwise and will usually taste bland or even bitter.
Severely light-deprived radishes often have a mushy or chewy texture, too, so they won’t be any good.
Sun Requirements for Different Radish Varieties
As I’ve mentioned, radishes come in all sorts of varieties adapted to varying amounts of shade.
Now, to be clear pretty much all radishes can tolerate at least some shade, but not all can thrive in truly shady conditions.
Broadly, radishes that can deal with higher temperatures will do better with more sun more often, even when temperatures start to climb.
Though most radishes are classified as cool season crops, some like the black radish are significantly more heat tolerant, to the point that you can reliably grow them in the summer.
On the other hand, true cool season radishes like the common radish generally don’t want to be above 70 °F (21 °C), and accordingly they‘ll do just fine getting around 6 hours of sun and then shade in the afternoon.
No matter how excited you are to get your radishes growing, take the time to do a little bit of homework and figure out which ones will grow best in your region, your soil and in whatever spot you’ve picked out for them.
Whatever you’re dealing with, there is sure to be a radish variety that will work just fine for you.
Tips for Bringing Indoor Radishes Outside
If you started your radishes indoors, or have previously been growing them to completion and want to transplant them, you’ll need to harden them off before you move them outside full-time.
To do this, take your trays or pots outside, and leave them in a shady spot during the middle of the day for a couple of hours.
After 2 hours have passed, bring them back inside and repeat the process the next day, leaving them out for a little bit longer.
You’ll do this for a week or maybe two, each day leaving them out longer and longer, until the plants are fully acclimated to the outdoor conditions.
Patiently completing this process will prevent transplant shock which usually occurs when bringing indoor plants outside. If you don’t harden them off, or rush it, you can expect to lose some of your plants.
Tom has lived and worked on farms and homesteads from the Carolinas to Kentucky and beyond. He is passionate about helping people prepare for tough times by embracing lifestyles of self-sufficiency.