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

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02 Aug 17, Mike (Australia - sub-tropical climate)
A better suggestion is a Styrofoam box used for corn or zucchini - if you can find bigger boxes the better - you can grow more at a time. Go to Foodworks, IGA or any supermarket and ask if they have any. Put newspaper, shade cloth or bubble wrap on the bottom - then about 25 mm of small pebble (the beach) - then another layer of paper, shade cloth or bubble wrap with some holes in it. Mix up some soil, sand, compost/manure and potting mix/seed raising mix. Put that in the box and give a good watering. Plant the radish and sprinkle some soil/ potting mix/seed raising mix over the radish. Keep out of the sun until they germinate or put some shade cloth or something similar over them until they germinate. With this free draining soil and shallow soil depth they will need watering each day and plenty of sun. Have 2-3-4 boxes and have a succession of plantings. This method can be also used to grow lettuce and baby spinach - plant very densely and cut the young leaves about 25-50 mm up the plant and they will reshoot - multiply cuttings. You can buy seeds on the internet 100-200 seeds for $1.
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15 Feb 17, Millicent (Australia - temperate climate)
Mine were red and green
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09 Feb 17, Danny (South Africa - Summer rainfall climate)
My radishes grow all top but no bulb. Any ideas.
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10 Feb 17, Julie (New Zealand - sub-tropical climate)
Hey Danny, me too! I thought I hadn't planted the seeds deep enough or firmed down the soil hard enough after planting seeds? Will be giving these a go next lot as mine are also growing more above ground than below.... hope these ideas help!
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09 Feb 17, John (Australia - temperate climate)
The most common cause of lots of leaves and small roots in radishes is an excess of manure which has a lot of nitrogen in it. Nitrogen is what causes leaf growth and is ideal for lettuces, spinach, etc. If you have used a lot of manure plant a leaf crop to use up some of the nitrogen then plant your radishes.All the best.
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04 Nov 16, lana (Australia - temperate climate)
why did my radish look great when harvest,but were not nice .soft and spongy airy inside.
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16 Jan 17, Amy (Australia - temperate climate)
I have read that that can happen if you leave them in too long, could that have been the case?
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04 Sep 16, Purpleluna (Australia - temperate climate)
Yes I am and my son are going to plant these type "sparkler" in a deep old stainless atell washing sink fr a laundry so I dont aee why not as the radishes are small
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30 Jun 16, Gomoco (South Africa - Summer rainfall climate)
already in the ground, thanks for you tip and weekly updates
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15 May 16, Ian (Australia - sub-tropical climate)
I've found main pests tend to be grasshoppers and caterpillers. You can grow them with daikon radish in between. They have bigger leaves and grow more vigorously so tend to attract pests. They are also reported to be good for soil system in similar way to rocket. In Japan they grow them in the rows between orchards for soil quality and to suppress pests.
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Showing 61 - 70 of 145 comments
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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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