Poor setting on outdoor tomatoes

[ken]

I've grown the early fruiting bush tomato Latah for about five years now, so I know it's a good variety. This year, though, the first trusses set very well (we've been picking tomatoes for about a fortnight) but later trusses have set very few fruit, despite me regularly giving the plants a gentle tap to shake the pollen. The four plants are outdoors, in big 10 inch pots as usual. I'm inclined to blame the wet, cold, dull weather we had as the blossom on the later trusses never really looked great. However, the compost might be a problem, too. It doesn't hold moisture well - water and feed run straight through into the saucers.

[Nature's Babe]

My outdoors tomatoes seem to be setting fruit well though I never bothered shaking them at all, plenty pollinators around still I guess. I erected a cover over them as there was so much rain, and too much detracts from flavour, left sides open for air circulation. Some are plum sized now and they look in fine fettle. The greenhouse toms are in big pots of my own compost and the flavour is superb, a taste sensation is the omly way to describe them I did try two grafted toms but not sure they are worth the extra expense when I see how well the outdoor ones are doing.

[Primrose]

My upright tomatoes have set very poorly and in case are now all gradually surcumbing to blight. Interestingly my yellow bush tomatoes - (I'm experimenting with 3 different varieties this year, Tumbling Tom, Tumbling Junior, and Balconi) have all set early and prolifically and I've already picked a couple of pounds from them. They don't seem to have reacted so badly to the weather and I'm hoping that as in previous blight years, I may get a reasonable crop from them before they get infected.

During my last blight year 2 years ago, my bush tomatoes seemed to remain virtually blight free and flowered & cropped earlier than the other varieties.

[ken]

Thanks, NB & P. Having had time to do a bit more reading up, I think the most likely cause is extremes of temperature, which we have certainly had this year. We didn't have any frost as such after I planted the toms outside, but there were some pretty cool nights, so covering with fleece next year might be a very good thing to do.