Author Topic: Progress Report  (Read 1616 times)

Tee Gee

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Progress Report
« on: January 20, 2018, 13:41:44 »
You may recall that earlier this month (8th) I said;

Quote
Usually I wait until my Snowdrops have appeared before I start sowing but strangely they have not appeared yet, ???? plus my spring bulbs do not seem to be as far forward as they usually are at this time of year.

Maybe this cold frosty snap might push them on a bit!

Well I saw my first snowdrop this morning so I prepared my hot bed and switched it on.

Might start on Monday or Tuesday as it might take me until then to regulate the temperature on my hotbed.

The thermostat switch on the bed  I find does not necessarily give the temperature it says on the control so I stick a soil thermometer into the sand,  then when it records the reading I want,  I take note of the setting on the control switch and fix it with tape so that it does not move if I accidentally bump into it as I often do.

So with a bit of luck the Onions will be sown early next week and hopefully I will have another successful year like last.



BarriedaleNick

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Re: Progress Report
« Reply #1 on: January 20, 2018, 18:33:40 »
So not having a hot bed what would be the best way to start my Exhibition onions.  I find if I germinate indoors they get very weak and leggy and the poly is really to cold.
Heated Propagator then move to the poly??
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Tee Gee

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Re: Progress Report
« Reply #2 on: January 20, 2018, 19:27:17 »
Hi Nick

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I find if I germinate indoors they get very weak and leggy and the poly is really to cold.
Heated Propagator then move to the poly??

Well I find with most seeds that highish temperatures are needed for germination but once germination has occurred then the temperature can be substantially reduced.

The key factor then is 'light' followed by temperature for example:

I germinate on a bottom heat of around 65°F (18°C) then once germinated I put them on the top shelf in my greenhouse which is kept at around 40°F (4°C) so that they get maximum light.

IMHO I always consider that it is the lack of light rather than the low temperatures that  causes the weak and leggy growth.

My belief is that  the leaves are effectively "solar panels" and these can not generate any energy if the light is poor!

ancellsfarmer

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Re: Progress Report
« Reply #3 on: January 20, 2018, 20:42:12 »
Tee Gee,
Can you confirm that its necessary/desirable to keep the sand moist to fill any voids within the sand,ensuring that you get an even temperature spread and avoid hotspots /chilly areas? How long does your sandbed take to reach set temperature, and how quickly does it respond to adjustment? Have re-done mine this year but it wonder if its working correctly. Currently seems to be air temperature plus 8 degs C (Around 13deg C)
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Tee Gee

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Re: Progress Report
« Reply #4 on: January 20, 2018, 22:25:46 »

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Can you confirm that its necessary/desirable to keep the sand moist to fill any voids within the sand,ensuring that you get an even temperature spread and avoid hotspots /chilly areas?

I wet my sand for a number of reasons for example:

1) I think it preserves the cable and keeps it flexible. My cable is around  twenty five years old.

2)I found that by putting a plastic sheet over the sand this keeps it from drying out due to evaporation, plus it keeps the sand free of compost that may get washed out of pots/trays onto it.

I am still using the same sand that I put on the bed when I built it.

Back to the moisture retention; What happens is when the heat comes on the moisture condenses on to the underside of the plastic,then when the heat goes off the condensates seep back into the sand, meaning I only wet it at the start of the season.

In fact that was what I did today!

When I removed the cover today I found that a thin film of green algae had formed so I scraped it off then wetted the sand with water containing some fungicide.


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How long does your sandbed take to reach set temperature, and how quickly does it respond to adjustment?

Difficult one this as I have never timed the process, but I would say it is up to the desired temperature within twenty four hours of switching on. In terms of adjustment I never need to do this as the thermostat takes care of this.


 
Quote
Have re-done mine this year but it wonder if its working correctly.

Currently seems to be air temperature plus 8 degs C (Around 13deg C)

I will not know if my system is working OK until I check it tomorrow hence me using a soil thermometer to find out. Once I have checked the temperature I will set my thermostat +/- to my desired temperature.

Once I have done that this will be the last adjustment I will make all season.

In terms of general temperature in the greenhouse this is done by a 3kw fan heater.

All winter this has been set to keep my greenhouse frost free usually around 37*-38* F  about 3-4*C.

I keep check of this with a wireless sensor that relays the temperature in the greenhouse to an other sensor in the house so that I have no need to run up the garden to my greenhouse to check it.

Once  I start my sowing season I adjust the greenhouse thermostat to give me an ambient temperature in the greenhouse of around 45-50*F (8-10*C)

So with the relative high bottom heat of the hotbed and the general heat in the greenhouse all I do is move plants around to ensure they get the best light available, until it is time to put them into a cold frame or cool greenhouse.

 Some seasons I may protect the plants in the cold frame by covering them with fleece if the weather forecast is scheduling low temperatures.

Another thing I find with this system is that the air temperature is usually a little warmer above the hotbed than the greenhouse in general and that it is slightly humid.

This humidity is particularly usefull if taking cuttings, hence its development during the time when I exhibited Chrysants & Dahlias.

I hope that answers your questions.





ancellsfarmer

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Re: Progress Report
« Reply #5 on: January 21, 2018, 09:00:56 »
Thanks, a most comprehensive answer.
 I currently have no background heat switched on, the "new" greenhouse is mostly empty, therefore the sand bed is at a disadvantage. Also I intend (today?) to add insulation to the base. Hopefully this will raise the temperature closer to the 20deg .I have 'on the go' a germination cabinet project based on a recycled fridge, but am frustrated by extended delivery of thermostat gubbins from China. The intention being precisely regulated germination, with ventilation, followed by transfer to the sand bed which has UV lighting to grow on.
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BarriedaleNick

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Re: Progress Report
« Reply #6 on: January 21, 2018, 09:34:46 »
Thanks - I may start some off today.
Just off to look at a plot for my wife who is very excited!
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