Pink Beauty Radishes

Question

I’m a student at Pascack Valley High School. In our research class, my partner and I are growing radishes to test the effects of different sources of nitrogen. We planted our first round of radishes on January 12th. We grew two radishes for every one-gallon pot. We made sure that they were at least 1.5 inches apart. We gave them 6 hours of sunlight a day and watered them with an automated drip-irrigation system. However, when we were suppose to harvest them earlier this week, we found that none of the plants had any bulbs whatsoever. Their root systems were also very poorly developed. It was completely unexpected, as the leaves looked healthy (although they did look flimsy and small). So, we pulled out the radishes and decided to start over after we found out how to properly sustain radishes.

We were wondering if you could answer some questions we had about the pink beauty radishes. If you had the time to answer, it would mean a great deal to us!

Here are our questions:
1. Are one-gallon pots enough to hold two radishes? Or should we just stick to one plant per pot?
2. We are using a grow light for the radishes. Is six hours under the grow light enough, or should we increase the amount of hours?
3. Are there any reasons as to why the radishes were not at all developed? We were thinking that maybe there wasn’t enough sunlight and that the soil was too tightly packed. How packed should the soil be?
4. Do you recommend that we pre-germinate the pink beauty radishes before planting them? We did this by soaking the seeds in a wet paper towel overnight and then planting them the next day.
5. Do you recommend anything to hold up the radish plants? During the first two weeks, they grew so tall that they couldn’t support themselves, and they were constantly snapping/bending.

If you have any other tips, that would be extremely helpful!

Thank you so much for taking your time to read this!

Answer 1

We are happy to help you with your project.

1) That size is more than big enough for 2 radishes.

2) I would give them a little more time under the grow lights. 5 hours is the minimum they need, but the more light they can get, the healthier they will be. Also make sure to keep the lights just a few inches above the tops of the leaves.

3) It sounds like you had a nutrient problem. Most likely a lack of phosphorous, which is responsible for root growth in plants. Here is more information on that: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/phosphorus-plant-growth.htm

Were you using any fertilizers in the soil? If not, it would be a good idea to add some.

4) Pre-soaking the seeds helps to speed up germination. It is not necessary, but can speed things along. It is really a personal choice whether you do it or not.

5) This is something called “getting leggy” and is a sign that the radishes were not getting enough light (more info: https://www.gardeningknowhow.com/garden-how-to/seeds/leggy-seedling.htm ). As I recommended above, make sure the lights are just a few inches away from the plants’ leaves and increase the amount of light they are getting. This will prevent the seedlings from getting all floppy like that.