If you are planning on growing rhubarb in your garden this year, you might\nbe wondering how big they will get. That way, you can plan the number of\nplants and the amount of space you will need for your crop of rhubarb.\n\n\n\nSo, how big do rhubarb plants get? The stalks on a rhubarb plant are 2 to 3 feet (61 to 91 centimeters) tall. The plant itself is 2 to 3 feet (61 to 91 centimeters) wide, since the plant\u2019s stalks and leaves can spread in all directions from the roots.\n\n\n\nOf course, the quality of your rhubarb (if you get any at all!) depends on\nthe care that you give your plants. Let\u2019s take a closer look at rhubarb,\nincluding size, growing conditions, and time to maturity.\n\n\n\nHow Big Do Rhubarb Plants Get?\n\n\n\nThe stalks (that is, the edible part) of a rhubarb plant can\ngrow 2 to 3 feet (61 to 91 centimeters) tall on a mature plant. A mature rhubarb plant can have a spread of 2\nto 3 feet (61 to 91 centimeters) in all directions.\n\n\n\nRhubarb stalks can grow up to 3 feet tall - they have a green and\/or red color.\n\n\n\nThe leaves (the part of the plant that is toxic to humans) are\nvery large \u2013 some of the largest that you will see in your garden. I have seen rhubarb leaves up to 1 foot long\nand wide, but I\u2019m sure they can get larger than that!\n\n\n\nHow Long does it Take Rhubarb to Grow?\n\n\n\nRhubarb takes a long time to grow, so you must be patient to\nenjoy the stalks of this plant. It will\ntake at least 1 year before you can harvest any stalks from a rhubarb plant \u2013\neven longer if you grow them from seed!\n\n\n\nIf you buy rhubarb crowns and transplant them into your\ngarden, you should not harvest any stalks in the first year of growth. In the second year, you can harvest a\nfew. (Add a year to these time frames if\ngrowing rhubarb from seed.)\n\n\n\nRhubarb seeds will generally germinate in 2 to 3 weeks,\ngiven proper soil moisture and an ideal temperature of 70 to 80 degrees Fahrenheit\n(21 to 27 degrees Celsius).\n\n\n\nHow do You Know When to Harvest Rhubarb?\n\n\n\nAs mentioned above, you should not harvest rhubarb in the\nfirst year after planting, since the plant will need all of its energy to\ncontinue growth.\n\n\n\nUsually, you harvest rhubarb from May to July in the 2nd\nyear (if growing from crowns) or the 3rd year (if growing from\nseed).\n\n\n\nFor more information, check out this article on rhubarb from Johnny\u2019s Selected Seeds.\n\n\n\nRhubarb should not be harvested until the 2nd or 3rd year of growth. Make sure to cut off and discard the leaves at the top of the stalks!\n\n\n\nWhen you harvest rhubarb, use a knife cleaned with alcohol\nto cut the stalks. Wipe the blade with\nalcohol between cuttings, to avoid spreading disease between plants. Cut off the leaves from the top of the\nstalks, since they contain oxalic acid, which is toxic to humans.\n\n\n\nAlso, remember not to harvest rhubarb after a frost or\nfreeze. The leaves contain oxalic acid,\nwhich is toxic to humans. This toxin can\nmove from leaves into stalks after a frost or freeze.\n\n\n\nFor more information, check out this article on rhubarb from the University of Minnesota Extension.\n\n\n\nFinally, be sure to leave 6 stalks on the plant, so that it\ncan absorb sunlight and continue to store energy for future growth.\n\n\n\nWhy Is My Rhubarb So Small (or Thin)?\n\n\n\nNewly planted rhubarb will have small, thin stalks in the\nfirst year or two before the plant becomes well-established. Lack of water, nutrients, or sunlight can\nalso cause small stalks.\n\n\n\nFor more information, check out this article on small rhubarb stalks from the Iowa State University Extension.\n\n\n\nAlso, keep in mind that older rhubarb plants may end up with\nsmaller stalks if they become larger than the soil can support.\n\n\n\nIn that case, you can divide the rhubarb plant and\ntransplant the parts to different areas in your garden. If you do divide your rhubarb, do it in early\nspring, before the plants begin to grow.\n\n\n\nFor more information, check out this article on dividing rhubarb from the Michigan State University Extension.\n\n\n\nWhat do Rhubarb Plants Look Like?\n\n\n\nRhubarb grows close to the ground, with many stalks growing\nout from the root ball and crown. \nRhubarb stalks are tall, with red or green coloring.\n\n\n\nRhubarb leaves are large, with a rough texture, and provide plenty of shade to the lower parts of the plant. The leaves at the tops of these stalks have been cut off.\n\n\n\nEach rhubarb stalk has one large leaf at the top. A rhubarb stalk and leaf looks similar to\nSwiss chard, but much taller and larger, with much rougher leaves.\n\n\n\nIs Rhubarb Hard to Grow?\n\n\n\nRhubarb likes full sun, so be sure to plant them in an area where they get 8\nor more hours of sunlight per day. Avoid planting rhubarb in a place\nwhere they will be completely shaded by a tree or tall neighboring plants (such\nas tomatoes).\n\n\n\nRhubarb is a perennial, and they can live for 10 to 15 years or longer with\nproper care. Remember to plant rhubarb somewhere\nit can stay for many years without being disturbed.\n\n\n\nRhubarb grows best in well-drained, loamy soil with a pH of 6.0 to 6.8\n(slightly acidic). However, there are many other factors that affect rhubarb\ngrowth, including temperature, watering, fertilizing, and spacing. Let\u2019s\nstart with temperature.\n\n\n\nTemperature for Rhubarb\n\n\n\nRhubarb seeds are often sown directly into the soil outdoors, 2 to 4 weeks\nbefore the last frost. You can\nfind frost dates for your area on the Old Farmer\u2019s Almanac website.\n\n\n\nHowever, this may not be an option in a climate with a short growing\nseason. In that case, you should start your rhubarb seeds indoors 8 weeks\nbefore transplanting them into the garden. \n\n\n\n\nAnother option is to buy rhubarb crowns. \nYou can plant rhubarb crowns in early spring (as soon as the ground is\nworkable, or no longer hard with frost). \nYou can also plant in the fall after the crowns are dormant (4 to 6\nweeks before the first fall frost).\n\n\n\nFor more information, check out this article on rhubarb from the Old Farmer\u2019s Almanac.\n\n\n\nThe ideal (optimal) temperature for rhubarb seed germination is between 70\ndegrees Fahrenheit (21 degrees Celsius) and 80 degrees Fahrenheit (27 degrees\nCelsius).\n\n\n\nKeep in mind that these temperatures refer to soil temperature, not air\ntemperature. If you want to find out the soil temperature, use a\nprobe-type thermometer to check.\n\n\n\nIf the thermometer reads a temperature that is too low, then you have some\noptions. One option is to wait until the sun warms up the soil.\n\n\n\nTo speed up this process, clear away any debris, such as leaves or grass\nclippings, from the soil surface. Also make sure to choose a location for\nplanting that gets plenty of sun, so that it can warm up the soil faster.\n\n\n\nIf you are worried about a short growing season, you can also use a cloche\n(a plastic or glass cover) to trap some heat and warm up the air and soil near\nyour rhubarb seeds.\n\n\n\nA cloche can be made from a plastic water bottle to retain warmth and\nhumidity in the soil for seeds or seedlings as they grow.\n\n\n\nAccording to the Oregon State University Extension, \u201crhubarb can withstand down to 35 F without damage. Rhubarb needs at least 500 hours of winter temperatures between 28\u00b0F and 40\u00b0F to properly form new leaf buds.\u201d\n\n\n\nWatering for Rhubarb\n\n\n\nWater rhubarb deeply and less frequently \u2013 provide enough\nwater to get the entire root ball wet.\n\n\n\nWater rhubarb deeply and infrequently, and aim to get the entire root ball wet.\n\n\n\nPutting mulch on top of your soil will help to retain moisture, especially\nduring periods of hot, dry weather. If you find that you have a problem\nwith dry soil, check out my article on how to treat dry soil.\n\n\n\nOn the other hand, over watering your rhubarb plants (or any plants for that\nmatter) can lead to root rot and eventual death. The best way to decide\nwhen to water is to feel the soil with your fingers.\n\n\n\nIf the soil feels dry 2 or 3 inches below the surface, then go ahead and\nwater. For more information, check out my article on over watering your plants.\n\n\n\nTry to water early in the morning, rather than at night, to allow water to\nsoak into the soil before evaporating.\n\n\n\nFertilizing for Rhubarb\n\n\n\nOnce the ground freezes, cover rhubarb with 2-4 inches of\ncompost. For more information, check out my article on making compost.\n\n\n\nTo make compost, you can use kitchen scraps or yard waste. Compost is a great way to add organic material and nutrients to your garden.\n\n\n\nTo fertilize your rhubarb plants, use \u00bd cup of 10-10-10 fertilizer\naround each plant in early spring, before growth starts. After 4-5 years, you can switch to\nnitrogen-only fertilizer for most soils.\n\n\n\nFor more information on fertilization, check out this article on rhubarb from the Iowa State University Extension.\n\n\n\nSpacing for Rhubarb\n\n\n\nWhen you plant rhubarb crowns, bury the roots so that the\ncrown bud is 2 inches below surface of soil. \nLeave 3 to 4 feet between plants, with rows 3 to 4 feet apart.\n\n\n\nFor more information on spacing, check out this article on rhubarb from the University of Illinois Extension.\n\n\n\nConclusion\n\n\n\nNow you have a much better idea of how big rhubarb get.\u00a0 You also know a bit more about the care that is necessary to ensure a healthy crop of rhubarb in this year\u2019s garden.\n\n\n\nYou might also want to read my article on where to plant rhubarb for optimal growth.\n\n\n\nI hope you found this article helpful \u2013 if so, please share it with someone\nelse who can use the information. If you have any questions or advice\nabout rhubarb, please leave a comment below.