Here are some maturity times for some of the most commonly grown types:
Small radishes are either round or elongated, and are available in beautiful shades of red, pink, purple, yellow, and white, depending on the cultivar.
Most small varieties will be an inch or two wide at maturity.
‘Cherry Belle,’ a small, round, red type, can be picked in just 22 days.
‘Cherry Belle’
You can find ‘Cherry Belle’ seeds available at Botanical Interests.
‘Early Scarlet Globe,’ another red cultivar, will be ready in just 20 days from sowing.
‘Early Scarlet Globe’
Packets of ‘Early Scarlet Globe’ seeds are available at Eden Brothers.
And ‘French Breakfast,’ an heirloom cultivar that is red and white with elongated rather than round roots, requires only 28 days.
‘French Breakfast’
Seeds are available at High Mowing Organic Seeds.
If the varieties you are growing are small and round, or small and elongated, most likely the harvest time will be somewhere between 20 and 30 days.
However, there are larger types as well, and as you would expect, these require a longer growing period.
Many of the larger types can be kept for a long time in cool storage.
These will need up to 90 days to mature and generally reach three to four inches wide for round types, and up to two feet long for daikons.
‘Green Luobo’ is a wide, elongated, green cultivar that needs at least 60 days to reach maturity.
‘Green Luobo’
‘Green Luobo’ seeds are available at True Leaf Market.
‘Round Black Spanish’ is a round winter storage type that takes at between 60 and 70 days to size up.
‘Round Black Spanish’
You can find ‘Round Black Spanish’ seeds at Botanical Interests.
And there are many types of daikon – large, elongated radishes with pungent flavor that are usually white in color.
My favorite daikon cultivar is ‘Japanese Minowase.’ This cultivar will be ready in about 45 days.
‘Japanese Minowase’
Seeds can be found at Eden Brothers.
When you have an estimated harvest time in mind, check the crops regularly – a telltale sign that the roots are ready is the appearance of the tops bulging up above the surface of the soil.