I was thinking about growing sugar beets on my London roof terrace, so I was wondering what temperature it needs. I also have access to a greenhouse should it be necessary.
1One good thing to note is that sugar beets do best in deep soils, often using soil over seven feet down. To grow these properly to maturity, you will need a fairly deep bed.– J. MusserAug 1, 2014 at 1:04
@J.Musser Thank you; Sorry to disturb your holiday.– tropicalAug 1, 2014 at 4:36
Heh heh. Totally my own fault. Who but me checks this site from his mobile on vacation? Anyway, do you have a deep bed suitable for sugar beets?– J. MusserAug 1, 2014 at 6:01
1For what purpose would you want to grow sugarbeet? they're rather inedible, and need industrial processing to make use of the sugar (unless you're a good amateur chemist). I don't know if they might be put to use for brewing? The only use we ever put them to on the farm was for as a treat for pet rabbits.– SivAug 1, 2014 at 19:35
@Siv I've grown them just for cool, or for exhibition, or sometimes use them as livestock feed. Tropical doesn't necessarily want to eat them.– J. MusserAug 1, 2014 at 20:13
In regard to the temperature requirements of sugar beets, they prefer an even 65°-80° Fahrenheit (warmer daytime temp) for the first 90 days of growth, at which point the roots begin to swell, and the plant will prefer to stay within 5° on either side of 75° Fahrenheit daytime temps, and the same for a 45° nighttime temp.
As for other optimal conditions:
Soil pH - Test your soil. The pH should read between 6.5 & 6.8. Sugar beets will produce poorly under that level, so if your soil reads lower than 6.5, apply lime.
Water - Sugar beets need at least 16" of rain to mature, but more is better. I have used about 35" over the entire season (counting rain) with success.
Fertilizer - These are heavy feeders. Give them plenty of nitrogen, in a balanced fertilizer, all season for the largest roots and highest sucrose levels.
Soil Type - They are adaptive, but do best in a sandy loam with a high organic matter content. It must be water retentive but free draining. I have grown them successfully in a range of soils, but still recommend sandy loam, even over bagged mix (no soil).
Other points of interest:
Sugar beets can take 100-180 days from seed to maturity, depending on conditions and variety. Some may take only 90.
In limited root space, go with a smaller beet. They take less space and mature faster, too!
Watch for weeds, which are the first reason for failure at first attempts on growing this plant.
I've noted that there is almost zero pest/disease problems when grown under close to ideal conditions, but watch for slugs, flea beetles, earwigs, and the like.
Southern States: http://www.southernstates.com/articles/growing-sugar-beets.aspx
Purdue University: https://www.hort.purdue.edu/newcrop/afcm/sugarbeet.html
Heartland Outdoors: http://www.heartlandoutdoors.com/food_plotting/story/up_for_a_challenge_grow_sugar_beets/