Hi Folks – I was wondering if anyone could tell me if i’m doing something wrong. I have some herbs i’m growing from seed in seed trays (Chives, Rosemary, Basil)

And I have a 4 tier hothouse about 2 metres high a metre wide with 4 shelves BUT i’ve noticed the temperature inside is 50 degree’s Celsius.

Should I moving the hothouse to an area with less sunlight?

Hi AdamJD.
What is your general location? Melbourne, Sydney….?

If your little hothouse is reaching those temperatures then you need to release the excess hot air somehow. Hothouses are generally for winter use, when temperatures are usually too cold for seeds to germinate or some plants to survive outdoors. As the weather warms up then windows are opened during the day to allow excess heat to escape. 50 degrees is definitely too hot, so you need to leave the door or vent open during the day and close up again before it cools down too much at night. If that doesn’t work then relocation to an area that only gets partial sun, or some protection with some shadecloth might be needed.

Also once your seeds germinate, they don’t need to be kept in such sheltered conditions but gradually “hardened off” to the conditions that you want them to grow in.

Hope this helps. And come back to check this thread later to see if others have more (or different!) advise.

I’m in Penrith in NSW! It’s a hot place!

g’day adam.
if its hot what are they doing in a hothouse?
50 degrees will kill everything.
take them out and if their roots are well developed plant them.
how big are these seedlings ?
welcome – and scuse my gruff manner. i used to have a big hothouse that got to 50 degrees – luvly in winter but unliveable in summer.
i’ve got one of those four tier hotframes here in adelaide. my seedlings only get eastern light – morning sun – and they are a bit spindly – but if your seedling house can be moved to where it gets only eastern sun that might give them a better chance.

I’ve since moved it to the edge of a covered area that we sit under/have bbq’s etc.

It dropped to 35 degrees in no time (which is probably what it is here in general) but the house will still protect them from wind so I’ll leave them there.

Once I see anything green I’ll take them out of the hothouse I guess.

One more question – would the 50 degrees bother seeds? I mean nothing has sprouted yet?

Would a higher temp help them germinate?

AdamJD said:

One more question – would the 50 degrees bother seeds? I mean nothing has sprouted yet?

Would a higher temp help them germinate?

possibly – if they were kept damp.

basil can be planted direct into the garden when its hot.
rosemary usually grows from cuttings i think.
chives, onion, leek are best in seed trays for a start.
i’m not sure if 50 degrees would kill seeds ???
might be a good idea to replant just in case.

most seeds have an optimum temp for germination, depending on their type. Plants that are typically planted in Autumn and are grown over Winter like a minimum soil temperature of 10 to 20C for germination while some will germinate as low as 5C. Spring grown crops germinate best in minimum soil temperatures of 15 to 25C. I don’t know what a maximum temperature would be, but I would expect anything over 30C would be getting too hot. Note this is soil temperature, not air temperature. It would be worth testing the temperature of your mix. If there isn’t a spot you can stick a soil thermometre in your pots, then make up a pot with just damp seed raising mix just for the thermometre, and keep is watered the same as the others.

Is he talking hot house as in glass – in – frame, or shade house??? I’m confused as we only have shade houses here…

However, I think with AdamJD’s hothouse, he needs to consider his ventilation…

It’s not glass – it’s a tubular like frame that’s covered in a think clear plastic material.

Beg your pardon Adam: I’m totally not familiar with hothouses, quite the reverse…

OK, I think you have done the right thing with moving it. As the weather warms up, me, myself, my shadow and I would be monitoring the ventilation, but that’s just us…

I know when I first started out with shadecloth “fern houses” as we used to call them about 30 years ago, I eventually worked out that the lack of ventilation (cross-ventilation??) was creating a state of humidity that was causing my plants to wilt during the day…just a thought…

all such plastic or fibreglass hothouses need side ventilation. I was just doing grafting of cherries in a hothouse where the thermostat was set at 30ºC this week and .. once the temp reached 30.. the sides automatically rolled up the cross ventilation cooled the house sufficiently to auto close the sides again within a couple of minutes.. this went on all day., every couple of minutes the sides rolled up or down.

Of course, since we wanted to work in there and had at least four days of this, we switched the auto temperature regulation off whilst the sides were rolled up..

No plant essentially really wants the temperature to get higher than 35ºC as the plants tend to want to shut down after that.. as no doubt so do humans.

(Chives, Rosemary, Basil)

none of these plants needs a hothouse to germinate

I have germinated Basil whilst frosts are still occurring.. out in the full frost.