Abstract:
Hardening-off refers to a process where nursery plants are gradually introduced to environmental
conditions that are similar to the ones they are expected to encounter in the field when they are
transplanted. Hardening-off of tomato seedlings reduces transplanting shock which may be caused
by windburns, sunburns, and interrupted water uptake by the roots and breakages. The process also
helps tomato to toughen up and reduce chances of injury. Hardening significantly contributes to
increased productivity, this, in turn increase farmers’ income and thus economic development of
the county and country at large. The proposed study was aimed at investigating the effect of
hardening-off on re-establishment and subsequent growth of tomato. The study was carried out in
the University of Embu Horticultural farm from January to April, 2018. The experiment was laid
out in a Randomized Complete Block Design (RCBD) but hardening treatments on tomato
seedling was applied in the nursery bed. The treatments were as follows: T1 - Watering daily until
transplanting (control experiment); T2 - Watering daily until 4
week;
T3 - Reduced watering frequency from the 3
th
week, no watering on the 5
th
week, 2 days
during the 4
rd
week (skipping 1 day during the 3
rd
week); T4 - Reduced watering frequency from the
4
th
week and no watering on the 5
th
th
week). Data was collected
on plant height, number of branches and days to flowering. Data collected was subjected to
analysis of variance (ANOVA) using XLSTAT version 2016 to test for significant effects between
treatments and means was separated using Student’s Newman- Keuls (SNK) at 95% level of
confidence. Treatment 3 (reduced watering frequency from 3
week (skipping 1 day during the 4
th
week and 2 days during the 5
th
week, 2days during the 4
rd
week skipping 1 day during the 3
rd
week) and treatment 4 (reduced
watering frequency from the 4th
week and no watering on the 5th
week) recorded the highest rate of seedling survival after transplanting, plant height, number of
branches and days to flowering.
