Cosmos and Dahlias

[sleepingpup]

I have a large, wide bed in my south facing garden and I have ordered 10 chocolate cosmo plants. They have arrived but is it too early to put them in? what should I do with them in the meantime if it is?

I have also ordered some dahlias to plant alongside but they say they should definately not be put out yet so I have potted them into plastic pots and they are in my garage. Wasn't 100% sure which way up they went!

Generally Im making it up as I go along and I have no experience with these plants and just following my nose.

Any advice and tips from people with more experience than me?

Don’t put the Cosmos out until the danger of frost is over, usually around mid May depending where you live, keep them on a bright window sill and well watered, if you’ve not got a greenhouse.
When they’re about 10cms tall pinch out the top tips, then they will branch out to bushy plants.
It doesn’t really matter which way up the Dahlias go, they will grow towards the light, but don’t keep then in the dark.

My dahlia tubers went into pots about 3 weeks ago and are just starting to sprout now - they take a little bit to get going in my experience so don't panic. As @Beebumble2 says, they will need some light (and I think warmth) to get going. I have one of those little pop up greenhouses with the plastic covers, and I pop them on the bottom shelf. My cosmos a couple of shelves above are starting to really shoot up too!

When you plant your cosmos out depends a bit on where you are in the country - - in London I'll probably start hardening them off in a couple of weeks time.

Dahlias should be planted with the tubers down and the central stalk just pointing above the soil. I am in the south with a warm sheltered garden. So I have just brought mine out of the garage. The tubers put down roots first, then the little green shoots start to appear.

Because we are sheltered, I put mine in the garden when the green shoots are about 1 inch. Generally more harm is done by planting too early, than waiting. Just bring them to the light once the green shoots show and put them away at night, if frost is forecast.

Protect against slugs and snails too.

Stupid question. Do you keep your pop up greenhouse outside? I'm thinking it's a bit dark in the garage. @Tangelo

I am going to have to find some more plastic flowerpots from somewhere! Thank you both for your replies.

I use ice cream containers, water softener bottles and any plastic containers from the kitchen for my plants.

thanks @florentina1 and @Beebumble2 all really helpfull. i've been using these supermarket cartons. Does this look okay? ( got to be the world's most boring picture) Do I water them? worrying about damp.

What is in them?

@florentina1 there is a dahlia bulb in here.

Unless it is a small variety, you might need something deeper from the roots.

ah I see. need to get some deeper pots and more compost. I have about 7 of these like this and others in pots. thankyou good advice. @florentina1

Yes, you do need a much deeper pot. If your really struggling, an old plastic bucket with holes in the bottom would do. They need to be at least 10cms deep.
Plants will grow in all sorts of containers, as long as they’re deep enough and have some drainage. Old wellingtons, strong bags for life, wicker baskets could all become planters. It’s time to be creative! 😁

If I drilled wholes in one of those floppy garden trug bucket things and put them all in there at once? what do you think? @Beebumble2 @florentina1

Great idea! I grow mine, a two or three in each, in large plastic pots, due to slugs and snails.
Go for it 😊

Thank you ! very grateful .

need to get some deeper pots and more compost. Big yogurt pots, bottoms of 4 pint milk cartons. You need something 1.5 to 2 times as deep as it is wide. And if you decide to grow in containers for their whole life, you'll need to move to something at least bucket size.

@sleepingpup yes, my popup greenhouse is in the garden - - I keep it against a West-facing wall so it gets sun and some warmth from the bricks (in theory!)

all advice much appreciated! just realised I could use the 6 pint milk containers we go through at a rate of knots by cutting of the tops.

There is a total element of satisfaction in having to mend and make do isn't there.

Milk containers are great because you can see the roots growing. Use it as a science lesson😁