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If you’re an adventurous gardener and you find yourself constantly looking for new vegetables to try, then consider making black radishes your next experiment!
This guide will tell you everything you need to know about black radishes including how to grow them, how to harvest them, and even how to prepare them. These unique radishes will surely make an impression on anyone you share them with.
Keep reading to learn more about what makes black radishes so great and the steps you need to take to have a successful black radish harvest this year!
What are black radishes?
Black radishes are pretty much exactly what they sound like. Radishes that are black! They are an heirloom variety of radish meaning that their seeds have been passed down from generation to generation and that the plant has remained true-to-type over the many years.
They almost look like a lump of coal when they come out of the ground but once you cut into them you’ll find that they have a beautiful white interior much like the common red radishes we all know and love.
Although, what makes them different from their red counterparts is that they tend to have a much stronger flavor. They also grow to be larger than red radishes and also have a longer shelf life.
Why grow black radishes?
I think the real question is, why not grow black radishes? I’m a bit of an adventurous gardener myself so I like to try plants out that may be a little bit more uncommon.
Black radishes can add a quick burst of spice to any salad as they tend to be a bit spicier than their red counterparts as I mentioned earlier.
But don’t let their spiciness deter you! Simply roasting them or boiling them is enough to bring their spice down to a point that you won’t even know it’s there. But hey, I kind of like the spice so I might just keep eating mine raw.
And of course, black radishes are chock full of vitamins and nutrients like vitamins B and C which are important for boosting your immune system and providing your body with necessary energy.
Because they’re heirloom plants, black radishes are also a great candidate for seed saving if you let them go to seed over the summer.
How to grow black radishes
Before you get to growing black radishes, there are a couple of important things to take into consideration. The first of which is whether or not you will direct seed or transplant your radishes.
I prefer to direct seed mine in the ground instead of transplanting them. I find that radish transplants can be a little too fragile and oftentimes don’t transplant well.
Of course, if you’re growing in a colder climate, transplanting might be your only option to get an early start on your growing season.
When I direct seed my radishes, I like to seed them on the heavy side and then come back and thin them out later. This ensures that I get a good germination rate. But, thinning is an important part of this process.
If I don’t come back and thin out my heavily planted radishes, then they end up competing for space, water, nutrients, etc. This ultimately will leave me with radishes that are stunted in growth. Not exactly what I’m looking for.
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Black radishes and radishes in general are pretty low maintenance in that they’re not too picky about soil type. Of course, they would prefer loose, well-draining soil, but sometimes radishes can also be used as a cover crop to break up compacted soils.
If you find that you have particularly poor soil, then black radishes are a great option for container gardening.
Just make sure whatever container you’re using is deep enough to grow root crops. If your container is too shallow, then you run the risk of stunting the growth of your radishes. Aim to plant them in anything that’s at least a foot deep.
Make sure to water your radishes regularly and don’t let the soil dry out. You don’t need to completely saturate them but the soil should still have a bit of moisture to it when you touch it.
Radishes are pretty hardy so a lot of the time, rain does the work for you. But, if you live in a hotter and dryer area, then it will be important to figure out some sort of irrigation plan. That might look like a drip line, a rain barrel, or even just watering with your everyday garden hose.
We have a great article on how to take care of your garden in hot weather that you can check out here.
Whether you’re planting transplants or thinning out directly seeded radishes, your plants should ultimately end up about 3 to 4 inches apart from one another.
Remember, the further apart you space your seeds, the more likely your radishes are to get large. The closer your radishes are to one another, the smaller they will be.
One of the worst pests for your black radishes is flea beetles. Flea beetles are pretty much exactly what they sound like in that they are extremely tiny insects that look just like fleas and will destroy the greens of your radishes.
The best way to manage a flea beetle problem is to cover your radishes with some sort of netting or fabric. But this should be done in a proactive manner instead of a reactive manner. Once you see signs of flea beetles, netting isn’t going to help you much since the beetles are already on your plants.
To help get rid of flea beetles once they’ve arrived, use diatomaceous earth (DE) on your plants. Diatomaceous earth is a white powdery substance made from ground-up aquatic fossils. Sounds pretty cool, right?
Flea beetles won’t be able to chew through leaves that have been sprinkled with DE as they can’t digest it. This is because the microscopic DE particles are sharp and can cut the insect on the inside. It also will dry out their skin.
DE is a fantastic resource but is very quickly washed away by just a little rain. So, it’s important to continue to reapply after any rains come through.
When and how to harvest black radishes
Black radishes take a little bit more time to reach maturity than common red radishes. Depending on what size radish you prefer, it can take black radishes anywhere between 50 to 75 days to reach full maturity.
If you’re someone who prefers your radishes to be on the smaller size (think golf ball), then you’re looking at the lower end of the days-to-maturity margin.
But if you’re looking for something more along the lines of baseball-sized radishes, then it’s going to take a little longer.
Similar to carrots, black radishes will start to stick their shoulders out of the ground when they’re getting close to maturity. This helps give you an indication of how big your radishes are.
Harvesting your radishes can be as simple as just pulling them out of the ground. But, if your soil is a little bit more compact in your garden, the radishes may not come out as easily.
In this case, you can break up the soil using a digging fork or a shovel. Just be careful not to pierce or scar your radishes in the process. If you do accidentally damage some, just be sure to eat those sooner rather than later so as not to introduce any disease or rot into the wound.
- PRO TIP: Use a weeding hand tool to loosen up the soil around stubborn radishes. Be sure to check our recommended tools section if you want to get serious about gardening.
Another thing that’s important to mention is to give your radishes a little squeeze when they come out of the ground. They should be pretty hard. But, if you find that your radish has some give or squish to it, it’s probably gone pithy.
Pithy radishes aren’t all that great to eat because they have more of a mealy texture inside and just really don’t taste as good.
Radishes are a one-and-done plant meaning that you can only harvest them one time and then you have to plant more if you want to grow more.
If you don’t want all of your radishes to reach maturity at the same time, then consider succession planting or stagger planting them. Plant a couple of radishes every 2 weeks and they should reach maturity about every 2 weeks as well.
This will prolong your radish season and keep your kitchen from becoming overrun with black radishes.
Using your black radishes
My favorite way to prepare black radishes (and most vegetables for that matter) is to roast them in the oven. As I mentioned earlier, roasting removes a bit of the spice and also softens the radishes up a bit.
I’m a pretty simple cook myself so I just put a little bit of olive oil, salt, and pepper on my roasted radishes. You can also add in some garlic to add a lot of yummy flavor. Sometimes I’ll roast them with turnips too.
You can also sautee them and toss them into a nice veggie stir fry. Or, if cooking isn’t really your thing, you can slice them and just eat them raw on their own or tossed into a salad.
Have I convinced you to give black radishes a try yet? They’re really not all that different from the red radish varieties that so many of us enjoy. To recap, here are the important things to keep in mind when growing black radishes:
- Black radishes take longer to reach maturity than red radishes. You can expect your black radishes to be ready in about 50 to 75 days.
- Plant your black radishes in soil that is well-aerated and has good drainage.
- Be careful not to over-water your radishes and saturate the soil. The soil shouldn’t be bone dry either. A quick feel with your hands will tell you how the moisture is in your soil.
- Cover your radishes and use diatomaceous earth to keep away unwanted pests.
- Radishes should be planted or thinned out to 3 to 4 inches apart.
- Harvest your black radishes when you see their shoulders sticking out of the ground.
- Succession plant your radishes to prolong their season and not get overwhelmed by a radish abundance!
Check out these must-have gardening products
You don’t need much to start gardening, but some tools and products will make a difference in how comfortable and effective gardening can be for you. Here are my favorites:
- Garden Trowel. A good garden trowel will last you many years. I love how sturdy this hand trowel from WOLF-Garten is, the metal doesn’t bend and it has a nice grip.
- Trimming Scissors. I use them for delicate pruning and harvesting all summer long, and they’re super handy. These Teflon Trimming Scissors are extra nice because they don’t rust as easily.
- Dutch Hoe. Dutch hoes may seem old-fashioned, but there’s nothing like a quick sweep through the topsoil to get rid of small weeds – no bending required. I love WOLF-Garten’s selection: this dutch hoe coupled with their universal handle.
- Grow Lights. These grow lights from Mars Hydro are super strong, yet dimmable, so they fit every stage of growth. They don’t put out too much heat and are very economical.
- Seedling Trays. There’s an art to choosing the best size for seedling trays so that it holds the perfect amount of water and gives the roots enough room to grow. These germination plugs are perfect when coupled with 1020 bottom trays.
- Liquid Fertilizer. You’ll need to feed your plants from the seedling stage, all the way to fruiting. This organic fish & seaweed blend is a very versatile option. Use it half-strength for young plants and full-strength for established plants.
Browse our list of tools, fertilizers & pesticides, indoor growing products and seed shop recommendations – we hope you find our selection useful and it saves you some time!