The Best Growing Conditions For Rhubarb Outdoors

Growing Conditions For Rhubarb Outdoors

Finding the best-growing conditions for rhubarb outdoors can be challenging, especially for beginners. This doesn’t make it hard to start growing rhubarb outdoors. Instead, it provides you with an opportunity to grow a new plant in your garden. 

The rhubarb plant is a vegetable plant from the buckwheat family. It has a sour flavor and can be eaten as a fruit. Most people turn it into a pie, jelly, sauce, or dessert. You can cook it with sugar to make fresh juice. 

Such a plant with various purposes can be ideal for your home, especially if you love fresh foods from the garden. That means understanding what it takes to grow the plant from seeds to maturity. 

This guide will look at the best growing conditions for rhubarb outdoors for growing in containers. 

When to grow rhubarb outdoors?

Growing Conditions For Rhubarb Outdoors

The best time to plant rhubarb outdoors is late fall or early spring. During this season, the soil is warm, and there is enough sunlight. The plant does well in full sun, so, for it to grow well, you can start it at this period so that the sun can help it to grow. 

Plant rhubarb crowns in late fall when dormancy has started, so you can have the crop in spring. However, for rhubarb crowns, you can plant them in the spring when the soil is warm and soft. The crown’s roots might still be dormant, but this is the best time to plant crowns outdoors because of favorable temperatures. Ensure that the temperatures don’t go below 50 degrees Fahrenheit. 

Growing conditions for rhubarb outdoors

As you know, rhubarb is a hardy and perennial plant that grows for several seasons. Actually, when you start planting rhubarb outdoors, you shouldn’t harvest it during the first year of growing. 

So, what are the best conditions for growing rhubarb outdoors? 

Soil quality

For you to grow a healthy plant, the soil quality must be high. The plant requires well-draining loamy soils. Loamy soil has better water retention capabilities, providing the plant with more nutrients. 

More nutrients for the plant, the better its growth. Still, the plant requires more nutrients than other plants because it is a heavy feeder. It uses the extra nutrients to feed its large stalks and leaves. 

When growing rhubarb outdoors from crowns, you should add nutrients to the soil to improve the soil quality. Ensure you add balanced fertilizer or compost and mix it well with the soil to spread evenly. 

Before you add fertilizer, you can do a soil analysis to check for pH and soil nutrients. The pH doesn’t affect the plant. On the other hand, excess nutrients such as nitrogen can affect the growth of your plant. So, if you find excess nitrogen, add fertilizer with low or no nitrogen. 

If you are using soil such as clay, plant it in a raised garden bed to improve the growing conditions. If that’s not possible, you can place the container on a raised ground and ensure it has big holes for proper drainage. 

Enough sunlight

The plant grows well in an area with full sun. When planting rhubarb outdoors, you should place it in an area with access to direct sunlight throughout the day. Find a location where you can’t disturb it after planting. 

Also, the plant can grow in a warm shaded area that experiences afternoon shade. This is for those areas that experience hot months in a year. But, avoid placing it in the shade all the time because it can cause the stems to become thin. 

Water quantity

Rhubarb grows well in moist soil. Sometimes it can vary depending on the type of soil. Most people have a problem determining the amount of water for the plant. It is advisable to provide 1-inch of water per week. 

However, if you are good at taking care of your plants, use the finger test to check if the soil is dry. Only water when the soil is dry to avoid overwatering. Overwatering can cause the crowns to rot due to the wet soil. 

Temperature and humidity

The growing conditions for rhubarb outdoors are determined mainly by the surrounding temperature and humidity. Your plant can die due to cold or overheating.

The best climate for planting rhubarb outdoors is an average of 40 degrees Fahrenheit during winter and 75 degrees Fahrenheit during summer. At the same time, it can grow well in warm areas. 

Planting it in dry and hot climates will have thin stalks and leaves due to the excess heat and low moisture content. If you sense low moisture content in the soil, you can mulch around the plant to conserve moisture. You should know the type of mulch to add to your plants. 


As you have noted above, when growing rhubarb outdoors, you have to give it a lot of nutrients. Use compost or organic fertilizer. Avoid using chemical fertilizers on a young rhubarb plant. 

Check the amount of fertilizer you give the plant to avoid adding excess nitrogen or phosphorous. These two components can kill your plant if you use them in excess. 


Pruning involves removing flower stalks that are taller than leaf stalks. When the flower stalks grow bigger than leaf stalks, they start using more nutrients than leaf stalks, which can result in less growth of leaf stalks. 

So, pruning the unwanted big flower stalks will ensure the leaf stalks keep growing until they are mature for harvest. 

When should you harvest rhubarb plants?

You can start harvesting sparingly in the second season by using the best growing conditions for rhubarbs outdoors. And after the third year, you can start harvesting with a run of 8 to 10 weeks long during summer. Once you start harvesting slowly, it leaves room for the plant to grow properly. 

Harvests the plant stalks when they have grown 12 to 18 inches long with a ¾-inch diameter thickness. Add fertilizer to increase the nutrients so that it can grow thick for harvesting. If the stalks are thin, don’t harvest the plant until they are thick enough for harvesting. 

To harvest, twist the base of the stalk as you pull it from the main plant. You can use a sharp knife to cut the stalk, but it’s not advisable because it leaves the cut area vulnerable to diseases. If you insist on using a knife, ensure that you sanitize the knife before cutting. 

The best rhubarb varieties 

  • Canada Red
  • Cherry Red
  • Crimson Red
  • MacDonald
  • Valentine
  • Victoria
  • Riverside Giant