Tips on the move from trays before planting out fully

Fiann Ó Nualláin says it’s now time to shift seedlings from trays to an intermediate home before planting.

In February, productive gardeners are sowing like it’s going out of fashion. We are generating the crops now that we will later plant out in March, April and May to harvest and nurture over summer and autumn. 

I write all my articles from a dualistic viewpoint in part to address the chief concerns of a reader that may be a GIY or gardening novice — so I supply all the info needed to accomplish the task or understand the topic — and I also write as an experienced grower and aim to pepper the pieces with strong insights that seasoned gardens may appreciate too.

The idea is to improve your success rate at growing your own food and medicinal plants, and to celebrate the fun and life- enhancing pastime that gardening is — no matter how long you have been at it.

Because these articles are about growing seasonal food or taking advantage of seasonal healing potentials, the topics are not just relevant to the month, but to the very weekend as it falls. I hope they supply weekend- by-weekend advice just as it is needed.

And because on that score this is a full-on seed-sowing month – that’s the topic today. In February, productive gardeners are sowing like it’s going out of fashion. 

We are generating the crops now that we will later plant out in March, April and May to harvest and nurture over summer and autumn.

So while I looked at seed sowing and how to improve germination success a few weeks back, the next important step is how we handle those germinated seeds and get them into crop plants. This piece covers the next three moves after germination.

At this point, if you haven’t already sown, then before you even open the packet remember that you don’t have to sow the whole bunch at once, save some seeds for next month or the month after — and that way you will have a staggered planting and more importantly a staggered harvesting regime. This is known as successional sowing. 

It means you have lettuce or whatever coming into maturity across the summer and not on a single week with a glut you end up composting or foisting on some to be ex-friends.

Okay, so you sow — mostly into seed trays, some can go direct into soil (carrots, parsnips — the ones that don’t like root disturbance) and then a few weeks later you have had a successful germination and seedlings appear. Yippee! but what next.

Well, to create stronger seedlings you may have to go ‘thinning out’. It is not an easy task to sow seeds singly and well-spaced so that they will all sprout in a nice regimented line. 

I have been sowing seeds since I was a child and my seed trays can come up like a court case photo in a lawsuit against a bad hair plug clinic.

Larger seed no problem, tiny fiddly seed — forget about it. Maybe you have the patience, the jeweller’s magnifying eye- piece and skill with a tweezers but for the vast majority of us, the germinated seed tray can be over crowded, patchy, or there can be clumps of seedlings along the line of individually germinated seedlings. 

If those clumps continue to grow, their roots will entwine, they will compete for moisture and just weaken each other, so we thin back to a single seedling.

Thinning back means to carefully pluck out the excess and leave one behind. It seems like such a waste, but it’s the right thing to do. The tradition is to discard (compost the thinned out ones), but of course you can redistribute into the sparse patches or place straight into modular trays.

I like to mist after thinning — both the plant and the root zone to help minimise shock. For the most part it is as simple as that, but when you get to thinning carrot seedlings they smell as strongly as a mature carrot to a carrot root fly, so a great tip is to thin on a still day to avoid wafting the tempting aroma on the air. 

When thinning veg you can think of the thinning as micro-micro-veg and keep for a salad or sandwich. It’s not frugal, it’s the high nutrition value that will keep a spring in your step. Waste not; want not.

The thinned bunch can keep going now for a few days to two weeks; then it gets to the stage where we want to pot up the seedlings that are developing good foliage into small pots so they bulk up roots and really develop into individual crop plants. 

This moving on is known as ‘pricking on’ .We can hold a leaf and with a dibber or pencil, prise up the plant and lift it into its new pot.

How you know a seedling is ready to move is when the first true leaves emerge? This is the bit that confounds, but the first true leaves are really the second set of leaves to emerge. It’s a bit like milk teeth and adult teeth. 

The first leaves are just a bit of photosynthesis energy to get the next spurt of growth — they are often called the seed or cotyledon leaves — the true leaves come next and they can take the pressure of thumb and finger to help with the lift, or more to the point to hold plant steady while you transplant.

Never hold by the stem or roots. Always transplant into a firmed compost, previously watered but not soggy with a receiving hole (pencil dipped in), for the swift movement from tray to new temporary home. Watering-in will fill the remainder of the hole (and push the roots into firm contact) with the growing media. 

Not every seedling copes well with transplanting, so start with the sturdy ones and get as far as the number of pots you have to fill. 

In a few weeks, the roots will fill the new pots and you will have a sturdy enough plant to plant outside (if frost has passed).

Hardening off is a move outside but not directly into where you want the plant to grow. 

Frost has not always passed by April or even May, but by moving your windowsill potted crops to a cold frame or unheated greenhouse/ polytunnel that lets them acclimatise from your kitchen to a halfway house and then eventually into the garden. 

The straight from centrally heated home to raised bed can be a shock too strong for some plants – so we take gentle steps.

Some gardeners have their pots in trays and place the trays outside by day and bring them into a shed or greenhouse at night to avoid the low drops of night temperatures. I just use some fleece. 

However, you want to protect your plants in this toughening up stage and eventually just want to plant out and get them under way proper. As to when — well that’s very often from April on.

You don’t want to get your crop’s root-bound and if you’re moving them on more than twice into bigger pots then you are probably being too fussy.


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