Stopping (end-of-season pruning)
At the end of the season, pinch out the top of plants and remove flowers and fruit that are too late, to concentrate strength on the fruit already set.
Explanation
When harvest is near and new flowers won't have time to ripen before the cold (check the calendar), you 'stop' the plant: pinch off the stem tips and remove the last flowers and small fruit. The plant stops spending its energy on new growth and redirects it to the fruit already in place, which swells and ripens better. Use the same moment to remove faded, damaged or diseased leaves and fruit, simple garden hygiene that limits the spread of disease.
Refined definition
'Concentrating the sap' is an image: physiologically, it's about redirecting resources to the fruit already set rather than to growth that will yield nothing before winter. The textbook case is the tomato, but the principle holds for many fruiting vegetables and fruit trees at the end of their cycle.
Key points
Pinch out at end of season
On tomatoes, pinch out the top of the stem two leaves above the last truss you keep (RHS: after ~4 trusses outdoors, ~7 under glass) and remove the late flowers: the energy then feeds the fruit already formed, not flowers that won't ripen. Source: RHS, Tomatoes.
Tidy up as you go
Regularly remove damaged, faded or diseased leaves and fruit: this is garden hygiene (prophylaxis), which limits the spread of diseases and pests, a gesture distinct from pinching, but complementary.
Watch out for
- • Not to be confused with formative pruning: stopping is done at the end of the cycle, when there's no longer enough good season left to ripen new fruit.
- • Don't compost the diseased parts you remove (blight, clubroot…): you'd spread the pathogens.
Examples
Sources
- RHS (Royal Horticultural Society) : How to grow tomatoes (rhs.org.uk/vegetables/tomatoes/grow-your-own)