STAND ESTABLISHMENT OF DIRECT-SEEDED TOMATOES UNDER HEAT STRESS

Stands of direct-seeded tomatoes may be markedly reduced under a high temperature regime due to thermoinhibition of germination, rapid drying of the medium surrounding the seed, and mechanical impedance of emergence due to soil crusting.
Establishment techniques employing priming or pregerminating seed and the alteration of the seed microenvironment with soil amendments were field tested to assess their effects on the seed and uniformity of tomato establishment.
Priming tomato seeds in a solution of 1.5% K₃PO₄ + 1.0% KNO₃ for 6 days at 25°C significantly reduced mean days to emergence over untreated seeds under supraoptimal temperatures without affecting total percentage emergence.
The use of seeds pregerminated for more than 48 hours resulted in severe reductions in final stands.
A peat-vermiculite vegetable plug mix amended with a polyacrylamide gel reduced mean days to emergence for both primed and untreated seeds and increased seedling dry weights at 21 days after sowing compared to seeds sown in unamended soil or fine-textured calcined clay anticrustant.

Symposium on the Timing of Field Production of Vegetables

G.B. Odell, D.J. Cantliffe

https://doi.org/10.17660/ActaHortic.1987.198.2