Is your rhubarb not growing well? You're probably making this common mistake

Rhubarb is an easy plant to grow, but you must remember to do this one thing to help it thrive

rhubarb growing in a garden
(Image credit: Getty / Jacky Parker Photography)

The most common mistake when growing rhubarb may surprise you – probably because, like many gardeners, you've forgotten all about this essential step in the growing of this popular plant. 

The great thing about learning how to grow rhubarb is that it's mostly very, very easy. Rhubarb doesn't care if the weather is wet or dry, it thrives in sun or semi-shade. Once your plant is established, you can harvest it multiple times per year. That's a lot of rhubarb crumble.

However, if you keep making this one mistake, eventually you'll get poorer yields and possibly even weak or diseased plants. The mistake is not fertilizing your plant twice a year with the correct fertilizer each time.

Luke Marion of MI Gardener says that this is the mistake 'a lot of people make.' He reminds gardeners that because rhubarb is a perennial plant, it needs to be fertilized twice a year – once in spring and once in the fall. 

It's 'the one thing you'll want to continue to do with your plants' – they need a nitrogen-rich fertilizer in spring (all-purpose or chicken manure) and phosphorus-rich fertilizer like blood meal in fall. The phosphorus 'helps establish the root base so it [the rhubarb] can get through the winter'. 

Get these two the wrong way around, and you're 'in deep trouble', because you'll be giving wrong nutrients for the growth stage the plant is in. Don't fertilize at all and you'll start getting less of a yield and thin, spindly stalks even on mature plants. 

You may even choose to fertilize your rhubarb three times, especially when growing in raised garden beds, applying more of the spring fertilizer during the active growth in the summer. 

The second most common mistake when growing rhubarb

Growing rhubarb

(Image credit: Getty Images)

The other mistake people often make is harvesting rhubarb during its first year, or over-harvesting during the second. 

Rhubarb plants needs two years to fully develop, and if you want a reliable harvest from your plants for years to come, you shouldn't touch it at all in its first season and only take a couple of stalks off each plant in the second. From the third season onwards, you can harvest your rhubarb fully. If you're not sure about the best time to harvest your crops take a look at our guide on when to harvest vegetables

These tips will hopefully see you dining on rhubarb crumble and tart very soon.