Watering when frost is expected

[Primrose]

My soil is so dry that seeds in my veg patch are proving very slow to germinate.Will I help to speed up the process by watering when frost is expected or will this do more harm than good and just reduce the soil temperature? I am torn.

[PLUMPUDDING]

I don't know the experts' advice about this, but have watered the shallots, garlic and onions plus some transplanted herbaceous plants and they look a lot happier despite two slight frosts. Can you put some fleece over them or cloches if you water them, that should help keep some warmth in the soil and help them germinate.

I used to think Dad was crazy dashing out to water his newly planted out runner beans when frost was forming at daybreak, usually at the end of May when you think it's safe. I think that's slightly different though.

I suppose the question is does moist soil cool more than dry soil. I think from observation that unless it is a severe frost it won't make any difference and watered plants will be able to cope better than dry stressed ones. Plants wilt automatically when it's cold to increase the concentration of their sap which acts like anti freeze to cope with a slight frost.

[Primrose]

I think the answer to this may be that it depends on how and where the water is distributed. I imagine that if you're able to water very slowly and gently, directing the main flow of water directly to the roots of the seedlings, hopefully the water will spread down more than be dispersed across the surface of the soil where it may do more damage. Anyway, I have watered the strawberries again today and some swede, cavolo Nero seedlings and peas and will keep my fingers crossed.

[tigerburnie]

I water in the morning, then they have all day to dry or get ready for the cold, works for me.

[Westi]

Interesting question Primrose!

I only water outdoor plants in the morning, so the plants aren't sitting in the damp overnight, in fact the very topsoil is dry before I leave the allotment in the afternoon. I suppose the question though is what happens when it actually rains? But you can't compare as when it is cloudy it is slightly warmer anyway - enigma hey?

[Pa Snip]

I believe watering is best executed of an evening. This allows plants to take up more water overnight
Watering in the morning means that there is less benefit reaching the plant as the temperature dries soil out during the day and evaporation takes place.

The exception is In cold conditions, and especially when frost expected, when there is little point in watering as the cold wet soil could freeze around roots