Rhubarb Stalks Thin: Crowded Crowns plus Heavy Picking
Rhubarb stalks thin out when clumps grow old plus crowded, when plants are picked too hard or when they lack food plus water. Utah State University Extension notes stalk size drops as plants age plus crowd, while University of Wisconsin Extension advises taking no more than a third of the leaves a year.
The short answer
Utah State notes stalk size depends on plant vigor, age plus variety. Overharvesting, poor nutrition, low water plus temperature stress all shrink stalks, plus stalks get smaller as plants age plus crowd. Divide old clumps, pick lightly plus feed every spring for thicker stalks.
Why are my rhubarb stalks skinny?
Utah State lists overharvesting, poor nutrition, too little water plus temperature stress as causes of smaller stalks. Older, crowded plants also give smaller stalks.
| Cause | Sign | Fix | Source |
|---|---|---|---|
| Old crowded clump | Many thin stalks | Divide every 5 to 10 years | Utah State |
| Overpicking | Fewer, thinner stalks | Take no more than a third of leaves | Wisconsin |
| Poor nutrition | Small stalks | Compost or fertilizer each year | Minnesota |
| Dry soil | Slow growth | At least 1 inch of water a week | Minnesota |
| Flower stalks | Less leaf growth | Remove them as they appear | Utah State |
How much rhubarb can be picked?
Utah State advises no harvest for the first 2 years, 3 to 4 weeks in the third year plus 6 to 10 weeks after the fourth year. Wisconsin advises never removing more than a third of the leaves in any year. Minnesota stops harvest at the end of June.
Does rhubarb need feeding?
Minnesota notes rhubarb is a heavy feeder plus advises compost or a balanced fertilizer every year. Utah State advises a granular fertilizer just before leaves emerge in spring, but not in the year of planting.
How to: step by step
- Count each plant’s stalks before picking.
- Leave at least two thirds of the leaves on the plant.
- Stop picking by the end of June.
- Spread compost around the crown yearly.
- Water at least 1 inch a week in dry weather.
- Divide crowded clumps in early spring.
Troubleshooting
Many thin stalks: a crowded clump. Divide it in early spring.
Fewer stalks yearly: overpicking. Take no more than a third of the leaves.
Small stalks after a dry year: Utah State advises extra water during harvest in dry years.
Seed stalks forming: Utah State advises cutting flower stalks as they lengthen.
For plant stress see the effects of environmental stresses on weed plants, underwatering cannabis plus mulch for cannabis. Kind Seed Co also stocks cannabis seeds.
Sources
- Growing rhubarb in home gardens, University of Minnesota Extension
- How to grow rhubarb in your garden, Utah State University Extension
- Rhubarb, Rheum rhabarbarum, University of Wisconsin Extension Horticulture
- Rheum rhabarbarum (rhubarb), NC State Extension Gardener Plant Toolbox
FAQ
When does rhubarb harvest end?
University of Minnesota Extension ends harvest at the end of June, then lets all leaves grow to rebuild reserves. Wisconsin notes vigorous established plants can be picked sparingly through summer. Utah State advises picking mature plants for 6 to 10 weeks or until plants lose vigor.
Should young rhubarb be picked?
Minnesota advises waiting until the second season, or the third if grown from seed. Utah State advises no harvest for the first 2 years, then 3 to 4 weeks in the third year. Wisconsin advises picking young plants only in spring so they can build size.
Does rhubarb need full sun?
Yes. University of Minnesota Extension advises a spot with all day sun. Wisconsin advises full sun where plants can stay undisturbed for years. Utah State advises spacing plants about 3 feet apart in a sunny area so crowns have room to grow without crowding each other.
How long do rhubarb plants live?
Utah State notes rhubarb can live 10 to 15 years. It advises dividing plants every 5 to 10 years, while Wisconsin advises dividing every fourth or fifth year. Dividing restores stalk size, since older crowded plants give smaller stalks as they age, per Utah State.
How do you divide a rhubarb crown?
Minnesota notes rhubarb forms next year's buds at the outer edges of the crown, while the center may stop producing stalks. Dig the clump in early spring, cut it into sections that each carry buds, then replant them about 3 feet apart, the spacing Utah State advises.
