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Messages - David Pilling

Current Photographs / Re: June 2024
Yesterday at 05:59:18 PM
Pictured today - my pot of red, orange and yellow Asiatic lilies. Zantedeschia aethiopica has been having a good year here, in a few neighbouring gardens - it has been a cold Spring in the UK.
General Discussion / Re: Vapour-pressure deficit
Yesterday at 05:21:40 PM
Peter - really interesting to hear about professional greenhouse users.
General Discussion / Re: Vapour-pressure deficit
June 10, 2024, 06:06:06 PM
The Govee app says

VPD Instructions

The Vapor Pressure Deficit (VPD) is the difference between the saturated water vapor pressure and the actual water vapor pressure in the air at a certain temperature. It indicates the extent to which the actual air is far from the water vapor saturation state i.e. the degree of dryness of the air.

VPD has an impact on the closure of stomata, thus affecting the physiological processes such as transpiration and photosynthesis. It has an important impact on the evaportranspiration process and water use efficiency in forest ecosystems.

I found a quote:

"The optimal vapor pressure deficit range for most plants is considered to be between 0.4 kPa and 1.6 kPa. This, of course, differs among plants. Each plant has its own sweet spot for different stages of development. As a rule of thumb, VPD should be on the higher side of the optimal range during later stages."

No surprise that in my greenhouse max 2.82 kPa min 0.22 kPa
General Discussion / Re: Plants in the News
June 10, 2024, 05:44:56 PM
Volunteers needed to halt Himalayan Balsam menace

An appeal has been made for volunteers to help clear Himalayan Balsam from a site owned by the Woodland Trust.

The plant is considered an invasive species in the UK and has taken hold across the country - including at the Smithills Estate near Bolton.

It is hoped volunteers can help remove the balsam before the plant flowers in July and August and the seeds are scattered across the ground.

Himalayan Balsam was first imported to the UK by Victorian botanists in 1839, as a garden plant. It has no natural rivals and can reach a height of up to three metres.

It can quickly dominate ditches and streams because its seeds travel in the water, meaning riverbanks can quickly become infested.
General Discussion / Vapour-pressure deficit
June 09, 2024, 05:26:38 AM
I got a new Bluetooth temperature/humidity sensor - Govee - whose phone app. wants to tell me the VPD - Vapour-pressure deficit.

"...the difference (deficit) between the amount of moisture in the air and how much moisture the air can hold when it is saturated."

Did anyone ever bother about this in their greenhouse - seemingly it can have an effect on plant growth - see:

Mystery Bulbs / Re: Lovely white ?
June 06, 2024, 10:26:17 AM
General Discussion / Re: Pasithea caerulea
June 06, 2024, 04:46:41 AM
You can consult the gray beards:

PBS wiki:
PBS list:

although they spend a lot of time arguing about the spelling. It seems it can flower in its second year.

As a non-expert I'd guess keeping it from going dormant for as long as possible helps.
General Discussion / Re: Plants in the News
June 04, 2024, 05:12:31 PM
Tropical plants return to the SS Great Britain

Tropical plants that were once transported on board the SS Great Britain have returned to the Bristol-based ship, for the first time in more than a century.

The weather deck now features replica mini greenhouses or Wardian cases that were adapted in the Victorian era to transport living plants.

Along with the transportation of ferns, which became incredibly popular, the cases also carried orchids, which could command huge prices at the time.
General Discussion / Re: Plants in the News
June 04, 2024, 05:02:48 PM
Quote from: Diane Whitehead on June 04, 2024, 08:05:27 AMI guess you don't have to worry until you start to glow in the dark.

Special shout out to Brasil nuts which contain radium. Of course you already glow in the dark (and light), just not at short enough wavelengths to see with the eye.

General Discussion / Re: Plants in the News
June 03, 2024, 02:11:19 PM
Giant Hogweed reported along Grand Union Canal near Apsley

Walkers have been warned to avoid a dangerous invasive plant that has been taped off ahead of removal.

A large Giant Hogweed plant, which if touched can cause serious blistering, was reported to the Canal & Rivers Trust on the Grand Union Canal towpath near Apsley Lock over the weekend.
General Off-Topic / Re: Southern Germany flood
June 03, 2024, 04:03:33 AM
Martin - please keep dry.

l/m² are hard to comprehend after a lifetime of rain in linear measure - first inches and then today mm. Anyway for anyone else cognitively challenged, I confidently assert that 100l/m² is 100mm of rain (or 4 inches).

1 liter = 1/1000 cubic meter

liter/square meter = 1/1000 meter cubed/meter squared = 1/1000 meter == millimetre
General Off-Topic / Re: Southern Germany flood
June 02, 2024, 11:06:17 AM
Rescue worker dies, several thousand evacuated in southern Germany floods

Comes with video - wow - been little mention of it on UK news.
General Discussion / Re: Plants in the News
June 02, 2024, 03:48:24 AM
7 beautiful foods to plant in your garden

Do you want to grow food in your garden without overhauling it into an allotment? Or wish you had a veg patch but don't have the time? You can have the best of both worlds, by scattering edible plants among your borders or in pots on the patio.
General Discussion / Re: Plants in the News
June 02, 2024, 03:46:59 AM
Quote from: Diane Whitehead on June 01, 2024, 05:53:23 PMMaybe just the ones they grow in Iceland.

Potassium is radioactive, bananas contain potassium, hence why they are a good addition to compost.

General Discussion / Re: Plants in the News
June 01, 2024, 05:43:31 PM
Quote from: Diane Whitehead on June 01, 2024, 08:39:01 AMIt's a good thing I eat a banana every day

Bananas are radioactive - more sanely healthier when eaten unripe - less sugar (?).