[Goneterseed]

There is always a lot of discussion on our plots about whether we should protect the bed by sheeting them up or not. I have tended to prefer to leave the soil open to the elements and to the wildlife to have a kick around and find winter food supplies.
Current rainfall is making me consider the option of trying to keep my soil from being waterlogged, getting compacted by the constant weight of the water.

I would be grateful for opinions on this please.

[BabbyAnn]

I think you answered your own question there - in a "dry" winter (as in cold and frosty), beds probably do benefit from being left open for reasons mentioned, but in a wet one, protecting the (clay-type) soil from being compacted or leaching out of nutrients (from sandy soil) with covers would be best.  Doesn't always prevent waterlogging though as the water table rises from areas already soaked.

The added benefits of covering especially with black plastic is that the soil will warm up earlier in spring (heat from sun) and may encourage some weed seeds to germinate early (which die under the cover or easily hoed off when the cover is lifted) However, leaving beds open in the cold will help to knock down pest numbers.  So IMO, there's no right or wrong answer.

[sunshineband]

I always cover my empty beds once they have their compost blanket and are good 'n' wet. The worms appreciate the extra protectiontoo  ieckon, as they seem to do a good job under the black plastic.

There are plenty of beds where there are still crops growing so it does not make the plot look hideous either, and althugh it is ot strictly an organic practice, it sits comfortably with ow we are growing our food.

And of course it does warm the ground a bit come the Spring too.

[Trikidiki]

Funnily enough I was going to ask a question about plastic sheeting last night but didn't get round to it. Perhaps it fits with this thread.

Does black polythene really heat the soil faster than clear polythene would? I understand that it will absorb radiant energy but wouldn't clear polythene let that energy through and therefore heat the dark soil anyway. Possibly even more effective as it is not actually heating the plastic which would then lose the heat to the air, whereas the clear the heated soil won't conduct heat to the air so easily.

My thinking was that because many weed seeds require light to germinate, then the clear polythene may encourage more seeds to germinate that could be hoed off before spring planting takes place. With black polythene the seeds may not germinate until the covering is removed and therefore germinate at the same time as planted seeds requiring weeding between the wanted seedlings.
 
Thoughts of an idle mind. What do you think?

[cadalot]

Clear plastic just acts like a coldframe or propagator, black plastic absorbs the heat and prevents light getting to the weed seedling and warms the ground up.

I now have full sheet for the winter cover up and sheets with pre burnt planting holes in patterns to match what I'm growing in the bed. i.e. potatoes, sweetcorn, cabbages, sprouts. These sheets have X cut in them that allow pop bottles with the bottoms cut off to be put in upside down so I can water at depth and the weed membrane keeps the moisture in the ground.   

[BabbyAnn]

My thinking was that because many weed seeds require light to germinate, then the clear polythene may encourage more seeds to germinate that could be hoed off before spring planting takes place. With black polythene the seeds may not germinate until the covering is removed and therefore germinate at the same time as planted seeds requiring weeding between the wanted seedlings.
 
Thoughts of an idle mind. What do you think?

true, some seeds need light to germinate but I still have to turn the soil over (especially when planting potatoes) or raking fertilizer in so those seeds come to the surface anyway.  Normally I sow small seeds in modules and grow on to plant out later and only the bigger seeds like peas and beans are sown direct when the soil is warmer - because the seedlings are chunkier than weeds, they are more easily recognised and then I can pick out the others.

The risk of using clear plastic is that as cadalot says, it will act as a propagator and encourage growth very quickly - if you only have a small plot or bed then I suppose it is manageable to keep on top of the hoeing but if you have a large plot, spring is such a busy time that it would be easy to forget about it and then end up with an overgrown bed.

[Trikidiki]

Clear plastic just acts like a coldframe or propagator, black plastic absorbs the heat and prevents light getting to the weed seedling and warms the ground up.

I now have full sheet for the winter cover up and sheets with pre burnt planting holes in patterns to match what I'm growing in the bed. i.e. potatoes, sweetcorn, cabbages, sprouts. These sheets have X cut in them that allow pop bottles with the bottoms cut off to be put in upside down so I can water at depth and the weed membrane keeps the moisture in the ground.   

I like your idea of different planting sheets with pre-cut planting holes and can see the benefit of black sheet as a weed suppressant in the growing season. Do you use polythene sheet or a woven fabric? I have no water supply on the plot so the idea of rainwater running off the beds wouldn't work for me so I would have to use a woven sheet. I might give that a go this year.

My main point though is regarding the preheating of the soil in late winter/early spring. You comment that the black polythene absorbs heat, this heat is lost quickly once the source of heat (sunlight) is removed. If you used clear polythene the radiant heat goes through the polythene and warms the soil beneath. When the source of heat is removed that heat is trapped under the polythene. My query is would the overall heating of the soil be more under clear or black polythene.

true, some seeds need light to germinate but I still have to turn the soil over (especially when planting potatoes) or raking fertilizer in so those seeds come to the surface anyway.  Normally I sow small seeds in modules and grow on to plant out later and only the bigger seeds like peas and beans are sown direct when the soil is warmer - because the seedlings are chunkier than weeds, they are more easily recognised and then I can pick out the others.

The risk of using clear plastic is that as cadalot says, it will act as a propagator and encourage growth very quickly - if you only have a small plot or bed then I suppose it is manageable to keep on top of the hoeing but if you have a large plot, spring is such a busy time that it would be easy to forget about it and then end up with an overgrown bed.

I took on my plot about 5 years ago and have constructed thirty 8'x4' beds with a few odd edge patches. Unfortunately I inherited a fairly sizeable weed seed bank both in the soil and in the huge pile of 'compost' which appears to have been made using every seeding weed in the universe. My aim is to germinate as many of these residue seeds as possible prior to planting. Luckily being on very light soil I can get away with a 'minimal digging' system. Over the years the burden of weeding has reduced drastically and will hopefully reach the point of only having to deal with incoming weed seeds rather than what was left in the soil from years before.

I may be a little strange but I enjoy hand weeding and do it all with a hand fork.

[cadalot]

I use woven weed membrane but a warning for you, my first batch I just cut with scissors and it frayed, I have found that it is better to use a soldering iron and cut/melt the sheet when cutting off the roll and forming the holes of the X for the pop bottle. 

You can extend the pop bottles by putting 2 or 3 into each other and around my dwarf fruit trees in containers I use small pop bottles with a plug (small pop bottle filled with sand) to stop the evaporation.

[Trikidiki]

I used the woven membrane between the beds with a woodchip covering. Unfortunately I didn't realise how badly it frays. Since I realised, I have used a gas sodering iron to cut it, works a treat.

[Goosegirl]

Triki - regarding your question about plastic sheeting - it will help to keep the soil dry underneath and prevent any annual weed growth, but when you remove it perennial weeds will still grow, as well as residual annual weeds. To me it's a good way of keeping things in check whilst you get other areas ready for planting. As for the colour, black will absorb more heat which is transmitted into the soil beneath. Clear sheeting won't get as warm but the heat may be retained better. Time for a trial me-thinks - get your soil thermometer out and let us know.

[Trikidiki]

You read my mind, Goosegirl.  I might knock up a monitor to log the temperatures on two beds over a period of time and see how the temperature varies over time.

Just need some sunshine to test it.

[whitehill1]

I have tended to prefer to leave the soil open to the elements and to the wildlife to have a kick around and find winter food supplies.
Current rainfall is making me consider the option of trying to keep my soil from being waterlogged, getting compacted by the constant weight of the water.

Had similar dilema though I bought a roll of weed membrane. finally want to try mixed mulches. like some black plastic, some straw mulch, and some with sowing  fenugreek  in btw rows where I don't have to walk in. use fenugreek as greens and micro greens .so watching this thread with interest

[Trikidiki]

Five temperature sensors arrived from Hong Kong last week. I have built a circuit on an Arduino processor.

The program logs the temperature from the sensors every 15 minutes and writes the data to an SD card, the card can be retrieved and the data graphed in Excel.

The plan is to have one of my 8' x 4' beds divided in two, each half covered by ether clear or black polythene. One sensor just beneath each sheet in the centre of each half and one buried an inch under the soil in each half and one in the open air in the middle of the bed as a control.

Waiting for polythene sheet to arrive. Just need to sort out the power source and a waterproof box then we're away.

[sunshineband]

I just use an old soil thermometer if I am unsure if the ground is warm enough for seed sowing... or even my fingers.

Seems to work OK really.

I admire your creativity Trikidiki but I could not cope with all that over the growing space we have though

[BabbyAnn]

I just use an old soil thermometer if I am unsure if the ground is warm enough for seed sowing... or even my fingers.

Seems to work OK really.

I admire your creativity Trikidiki but I could not cope with all that over the growing space we have though

if I recall, it was an experiment to see which ends up warming up the soil better - covering with black or covering with clear plastic in spring .... I'd be interested to see the results