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Sowing & Growing Update - 22nd March 2023



At last some warm weather, and my seedlings and baby plants are definitely enjoying it. When I compare last month's photos to this month's there's definitely been lots of growing progress. I did however lose a few seedlings during the cold snap and I have resown these (mainly the February seeds) and thankfully as you will see from the photos below these have germinated quickly.


I am now at the stage of hardening off (see below) our autumn sown hardy annuals ready for planting out into my cut flower patches once the soil warms up at the end of March/beginning of April, while at the same time I'll be nurturing our more recently sown seeds so they are ready to plant out after the last frost.


Hardy annuals

As a general rule hardy annuals can be planted out in mid-spring as the soil begins to warm up. There's obviously regional variations, planting out can begin earlier in milder areas in the south and west and later in colder northern gardens. Ideally your hardy annuals need to be roughly fist sized before planting out, if they are still a little on the small side you might want to leave then in their pots for a few more weeks.


Half-hardy annuals shouldn't be planted out until late spring or early summer, after all danger of frost has passed. I use this online tool to help predict when the last frost date in our area

https://www.plantmaps.com/interactive-united-kingdom-last-frost-date-map.php


With the above in mind I've indicated below which plants are hardy and which are half hardy.


As a reminder here's a summary of everything to consider over the coming months to care for your seeds and baby seedlings.


Ventilation

Seedlings are prone to a condition called damping off, it's a fungus that enters young seedlings from the soil. Good air circulation, to reduce humidity, along with not overwatering, is key to avoiding this condition. As long as it's not freezing outside I open my greenhouse doors every day and on mild-ish winter nights (5 degrees celsius+) I leave the doors open all night too.


Watering

The most important requirement is, of course, water as small pots can dry out very quickly. However there's a fine balance as overwatering can cause damping off. I water most days but I try and keep my pots moist rather than damp.


Feeding

Around six weeks after sowing the seeds the nutrients in the compost may start to runout and the plant is looking unhealthy and starting to yellow. You might want to give them a liquid feed, something that is high in potash, like liquid tomato feed is ideal. Avoid high nitrogen feeds as they promote leggy growth which we want to try and avoid.


Pinching out

Pinching out benefits certain plants that have a tendency to shoot upwards and produce a leggy plant with only one stem. Pinching out encourages bushier growth, numerous stems and plenty of flowers. I have indicated below which plants will benefit from pinching out.


Potting on

If you turn your pots upside down and you can see the roots appearing through the drainage holes, it's time to transplant them into larger pots. Try and find pots that are one size larger, and carefully remove the plant by loosening the root ball so it comes out whole. Put it in the new pot on a base of fresh compost and fill around the sides with fresh compost too.


This is a photo of the cornflower I sowed in August and as you can see it needs to be moved to a larger pot.


Second/successional sowing

As many types of flower seeds can be sown over the next few months, now is a good time to consider if you want to do a second or third sowing of any of the seeds we sowed last year or earlier this year, I've indicated alongside each plant, below, in which of the forthcoming spring month/s they can be sown.


Hardening off

A few weeks before planting out into your patch the plants ideally need to be acclimatised to being outside, the process is called hardening off. This is done by putting plants outside during the day and then putting them back undercover at night for a week or so. Then leave them out overnight. If cold weather is forecast you might want to consider covering your plants with horticultural fleece. Half-hardy annuals are most vulnerable, I tend to find that the hardy annuals need less attention and even in the first week can be left out overnight if the weather is fairly mild.


The information below is grouped by the month the seeds were included in our Cut Flower Patch seed boxes. For the purposes of comparison, for each plant I specify the number of weeks since sowing as I am aware that not everyone is sowing their seeds at exactly the same time. The photographs were taken on the day of writing this blog.


The August Seed Box - Corncockle, Cornflower, Iceland Poppy, Nigella, Larkspur


Corncockle - Week 33


Classification: hardy annual


To feed or not to feed: not necessary


Pinch out: no


Over the next month: I already have some autumn-sown corncockle plants out in my patch which are doing fine. Some of them are starting to get a bit straggly so I have staked those by attached the plant to canes with some gardening wire.


Second sowing/successional sowing: Direct sow March to May.


Cornflower - Week 33

Classification: hardy annual


To feed or not to feed: not necessary


Pinch out: yes when about 15cm tall


Over the next month: I have some cornflower plants already out in my patch which are doing well. Like the corncockle I think they will benefit from staking in the near future so in preparation I have put the canes in place.


Second sowing/successional sowing: Direct sow March to May.


Iceland Poppy - Week 33

Classification: hardy annual


To feed or not to feed: not necessary


Pinch out: no


Over the next month: Last month I transferred my poppies into slightly larger pots as they were getting a little root bound, they appear to have benefitted from the additional space and nutrients. I am going to start to harden off some of the larger plants in preparation for planting out into my patch.


Second sowing/successional sowing: Direct sow March to May.


Nigella - Week 33

Classification: hardy annual


To feed or not to feed: do not feed


Pinch out: no


Over the next month: I've been a bit disappointed with my nigella this year, they seemed to go leggy very quickly. They are now in larger pots and are doing a little better but I'm going to leave them in a greenhouse a little longer in the hope they can get more robust before planting out.


Second sowing/successional sowing: Direct sow March to May.


Larkspur - Week 30

Classification: hardy annual


To feed or not to feed: not necessary


Pinch out: yes, pinch out the growing tips when around 10cm tall


Over the next month: In theory I should be hardening these off now but I don't think they look as robust as they should, they're a little 'thin'. I am going to pot them on and then harden off in a week or so if the weather remains mild.


Second sowing/successional sowing: Sow indoors in March to April.


The September Seed Box - Scabiosa, Snapdragon, Ammi Majus, Calendula, Orlaya


Scabiosa - Week 28

Classification: hardy annual


To feed or not to feed: not necessary


Pinch out: no


Over the next month: My scabious are looking nice and healthy, it's time to harden them off.


Second sowing/successional sowing: Sow indoors Mar to May.


Snapdragon (Rocket Mixed)- Week 28


Classification: half-hardy annual


To feed or not to feed: not necessary


Pinch out: yes, pinch out the growing tips when they have four sets of true leaves


Over the next month: Other than keeping my snapdragon watered and well ventilated I won't do anything with them over the next month, they are half hardy so wont be planting them out until after the last frost.


https://www.plantmaps.com/interactive-united-kingdom-last-frost-date-map.php


Second sowing/successional sowing: Sow indoors in March


Ammi Majus - Week 28



Classification: hardy annual


To feed or not to feed: not necessary


Pinch out: no


Over the next month: The ammi is a good size and ready to be hardened off.


Second sowing/successional sowing: Sow indoors March or direct sow Mar to June.


Calendula - Week 28


Classification: hardy annual


To feed or not to feed: not necessary


Pinch out: yes, when they reach around 10cm tall


Over the next month: After potting on my calendula into larger pots last month they are looking a lot more healthy. I've recently pinched them out and now I am going to harden off some of the larger plants.


Second sowing/successional sowing: Sow indoors Mar to April. Direct sow April to May,


Orlaya - Week 28

Classification: hardy annual


To feed or not to feed: not necessary


Pinch out: yes, pinch out the growing tips when they have four sets of true leaves


Over the next month: Again these are looking strong are ready to be hardened off.


Second sowing/successional sowing: Sow indoors Mar to May.


The October Seed Box - Sweet Pea Tango, Sweet Pea Mammoth, Achillea, Lavatera, Cerinthe


Sweet Pea, Tango - Week 24

Classification: hardy annual


To feed or not to feed: sweet peas are hungry plants, I will start to feed mine once they start to flower or sooner if they start to look a little limp.


Pinch out: yes, pinch out the growing tips when they have four sets of true leaves


Over the next month: As sweet peas don't like root disturbance I was hoping not to have to pot these on before planting out, but I think they've now outgrown their pots. As they shouldn't be planted out until late to mid spring I am going to move them into larger pots now.


Second sowing/successional sowing: Sow indoors Mar to Apr


Sweet Pea, Mammoth - Week 21

Classification: hardy annual


To feed or not to feed: yes, with a liquid tomato feed


Pinch out: yes, pinch out the growing tips when they have four sets of true leaves


Over the next month: My mammoth sweet peas have not done as well as the tango variety. The week 21 photo is from a second sowing so they are a little behind. Am going to keep them in the greenhouse for longer and keep pinching them out in the hope that encourages some bushy growth.


Second sowing/successional sowing: Sow indoors March to Apr


Achillea - Week 24

Classification: hardy perennial


To feed or not to feed: not necessary


Pinch out: yes


Over the next month: Am very pleased with the achillea as last year my crop was definitely lackluster but this year they are looking good. I think they benefitted from being potted on last month, I now will start hardening them off in a week or two,


Second sowing/successional sowing: Sow indoors March to May.


Lavatera - Week 24

Classification: hardy annual


To feed or not to feed: feed with a liquid tomato feed once a month


Pinch out: yes


Over the next month: Last month I gave my lavatera a light feed using diluted tomato feed. They've perked up and I am now going to start hardening off.


Second sowing/successional sowing: Sow indoors March


Cerinthe - Week 24


Classification: hardy annual


To feed or not to feed: feed with a liquid tomato feed once a month


Pinch out: yes


Over the next month: Last month I re-potted the larger cerinthe plants into larger pots, they're now ready for hardening off.


Second sowing/successional sowing: Sow indoors March


The November Seed Box - Godetia, Florists' Dill, Wild Carrot, Aquilegia, Astrantia


Godetia - Week 20

Classification: hardy annual


To feed or not to feed: not necessary


Pinch out: yes, when around 10cm tall


Over the next month: my godetia plants have grown very quickly, I've now pinched them out and will start to harden off in a couple of week's time


Second sowing/successional sowing: Direct sow April to May



Florist's Dill - Week 20

Classification: hardy annual


To feed or not to feed: not necessary


Pinch out: yes


Over the next month: The florist's dill doesn't appear to have grown very quickly, I'll leave these in the greenhouse for another month and just keep them moist.


Second sowing/successional sowing: Sow indoors all year round. Direct sow March to July.


Wild Carrot - Week 20

Classification: hardy annual


To feed or not to feed: not necessary


Pinch out: no


Over the month: Again these need more time in the greenhouse, I'll ensure the compost is kept moist.


Second sowing/successional sowing: Sow indoors Feb to Mar


Aquilegia - Week 20

Classification: hardy perennial


To feed or not to feed: not necessary


Pinch out: no


Over the next month: Although still quite small I've pricked out the aquilegia, they are looking good. Again I'll keep them in the greenhouse and water them when the compost is looking dry.


Second sowing/successional sowing: Sow indoors March to June


Astrantia - Week 20


Classification: hardy perennial


To feed or not to feed: not necessary


Pinch out: no


Over the next month: Although still quite small I've pricked out the astranthia, they are looking good. Again I'll keep them in the greenhouse and water them when the compost is looking dry.

Second sowing/successional sowing: Sow indoors Feb



The December Seed Box - Corn Marigold, Bergamot, Delphinium, Viola, Snapdragon (Appleblossom)


Corn Marigold - Week 9

Classification: hardy annual


To feed or not to feed: not necessary


Pinch out: yes


Over the next month: I was a little concerned about my corn marigold last month but now lots of the seeds have germinated, they've got their first set of true leaves and I've pricked them out. They'll stay in the greenhouse for a while longer.


Second sowing/successional sowing: Direct sow March to May


Bergamot - Week 9

Classification: hardy perennial


To feed or not to feed: not necessary


Pinch out: yes


Over the next month: I've had limited success with germinating these but I have a few good ones and I've pricked them out, although still quite small. These will stay in the greenhouse for a while longer.



Second sowing/successional sowing: Sow indoors Feb to Mar


Delphinium

Classification: hardy annual