Growing Radish

Raphanus sativas : Brassicaceae / the mustard or cabbage family

Jan F M A M J J A S O N Dec
P P P P P P P P P P P P

(Best months for growing Radish in New Zealand - cool/mountain regions)

  • P = Sow seed
  • Easy to grow. Sow in garden. Sow seed at a depth approximately three times the diameter of the seed. Best planted at soil temperatures between 46°F and 86°F. (Show °C/cm)
  • Space plants: 1 - 2 inches apart
  • Harvest in 5-7 weeks.
  • Compatible with (can grow beside): Chervil, cress,lettuce, leeks, spinach, strawberries, tomatoes
  • Avoid growing close to: Hyssop, gherkins

Your comments and tips

22 Dec 19, Madison (Australia - temperate climate)
This is my first time growing radishes, and I found that most of the leaves had been eaten through or had tough brown/yellow streaks. I believe it may be some sort of disease or they have been attacked by pests.
27 Dec 19, Another gardener (Australia - sub-tropical climate)
when it is wet and rainy the bugs and insect breed more, or that is their breeding time. I'm sub tropical and I try to grow radishes March to Oct. I'm finding I grow the best radishes late autumn winter. And try and have the soil a bit firm when planting radishes. I find if the radish has germinated and is growing and the soil is then compacted a bit by rain/watering you end up with radishes that look like a number 8 instead of a nice circle round.
11 Oct 19, Danny (New Zealand - temperate climate)
why are my radish going to seed? Have very big top and no radish.. have done for about 3 years .
14 Oct 19, anon (New Zealand - sub-tropical climate)
If they have very big leafy tops you are over fertilising BIG TIME. Plant radish after a leafy crop so that a lot of the N has been used. My experience is to grow radish into winter -sub tropical.
22 Sep 19, Gerty (USA - Zone 7b climate)
My radishes came out too small or not developed a full bulb/root at all. I used a peat based potting soil and compost + vermiculite also amended with fish/kelp emulsion. I am growing them in 6 inch deep flats with proper drainage holes. The variety is Cherry Belles, Rover, French Breakfast. Planted them in late summer for fall.
25 Apr 20, Dr. Peeper (USA - Zone 9b climate)
Sounds like your soil is too rich, probably in nitrogen.
11 Jan 19, paul stanley wood (Australia - sub-tropical climate)
why not try the white long asian type i find them better they last longer in the fridge crisper
14 Jan 19, Mike (Australia - sub-tropical climate)
That is a daikon radish . (More info here - www.gardenate.com/plant/Daikon?zone=3)
28 Oct 18, Mandy McGuane (Australia - temperate climate)
Hi!! Would anyone be able to give some advice as to why my radishes when I picked them today, found that the base of them were split and not very healthy looking, rough skin? Could there be an issue in the soil? Thanks in advance.
28 Oct 18, Mike (Australia - sub-tropical climate)
A bit of a contradiction - splitting maybe too wet and tough could be too dry. I find I grow the best radishes in the winter - a light watering each day.
Showing 41 - 50 of 144 comments

Your Black Spanish Radishes are a a winter variety - Germination (seed to seedling) happens at temps of 50f - 75f (10c - 24c) and will take 6 to 10 days. --they take anywhere from 30 to 70 days to mature (that is from sprouted seedling to harvest) - you can harvest them when they are about 3" to about 5". Plant anywhere from about two months before the first expected fall frost to 3 weeks before the first expected fall frost. Your best option is to figure out your first expected frost date - count back 8 weeks and call that your "expected planting date" - then check LAST years temperatures at or around your "expected planting date" -- if the temperatures sync up with the germination temperatures (10c - 24c) for Black Spanish Radishes, then it is a good time to plant, if not try and tweak your "expected planting date" so you will have the correct germination temperatures - and enough time for your radishes to grow. The reason your days to harvest has such a wide range is: you can harvest from 3" up to 5" -- additionally, when planting closer to fall/winter the number of hours of sunlight (and the intensity) varies a lot - for example: in my area on August 10th I get 14:36:05 hours of daylight .... and on September 30th I get 11:43:20 hours of daylight -- both are fairly good planting dates with August 10, 2022 having temps of (high/low) 20.4c/ 12.8c AND September 30th having temps highs of 20.4c and lows of 8.7c ==> but September has about 20% less daylight hours and the suns intensity is much weaker -- this means radishes planted in September will take longer to grow and mature than radishes planted in August.

- Celeste Archer

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This planting guide is a general reference intended for home gardeners. We recommend that you take into account your local conditions in making planting decisions. GardenGrow is not a farming or commercial advisory service. For specific advice, please contact your local plant suppliers, gardening groups, or agricultural department. The information on this site is presented in good faith, but we take no responsibility as to the accuracy of the information provided.
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