Wednesday, September 14, 2011

Pricking out seedlings

Do you know what 'pricking out' is?

If I wasn't a gardener, I really don't know what I would think of this term meant if someone mentioned it to me!

To prick out is to gently remove seedlings that have been sown together closely in order to give them more room to grow. If germinated seeds are left to crowd each other, none of them will grow to their full potential and they will strangle each other as they compete for light, nutrients and soil.

I've been outside in the greenhouse this morning, pricking out and I thought I'd share how I go about it. (I'm sure there are loads of different ways and each person would develop their own preferred method - I'd love to hear yours if you have a spare moment!).

So, to start off with, I have some heirloom tomato seeds that were sown a couple of weeks ago in the greenhouse. They were a little slow to germinate as we had an unexpected cold snap...


They were sown in a repurposed plastic tray in commercial seed raising mix.

As these tomatoes are going to be grown in our garden (that is, not destined for the daughter's plant stall or the school fete), I am pricking them out into newspaper pots, which can be then planted straight into the ground when the time comes..

Newspaper pots are quick and easy to make. My original method can be found here, although with these particular pots, I recall using an empty corn chip tube to creat a wider pot than my usual favourite tumbler!

The pots are filled with the growing medium. I prefer to use a commercial potting mix as I have had trouble in the past with seedlings 'damping off' (dying of fungal attack)  in homemade potting mix.

After the pots are filled, place them on a seedling tray to keep them all together and give them a water. I find seedlings really like going into damp soil.

Using a small twig or skewer, make small holes in each pot, approximately 1-2cm wide by about 2-3cm deep. This measurement may change, depending on what type of seeds you are planting, how large their roots are and whether or not you are aiming to develop roots on their buried stems...


Ever so gently, 'prick' the small seedling out of the tray, carefully using the stick to loosen the roots so it can be removed with minimal damage. Some people like to prick out when seedlings develop their first 'true' leaves (or second set of leaves) - as you can see, my seedlings don't have their first true leaves yet. I have been pricking out this way for several years and find it the most successful way for my method.

To remove the seedling at this stage, gently hold it by a leaf between your thumb and forefinger. It may seem to make more sense to clasp it by the stem but trust me, your little plant is much more tougher in the leaves and holding it this way is less likely to cause damage. Stems can be delicate little life centres!


Easing the seedling out by gently loosening the roots with a small twig
 Once the seedling is free, position it over one of the newspaper pots, placing it gently into the hole ensuring that the roots are well and truly in there!


Some seedlings can  have their stems buried to encourage extra root growth. Tomatoes fall into this category.  Fill in the hole around the seedling using the stick to move the potting mix into place.

The tomato seedling, transferred to newspaper pot with the majority of stem buried to encourage extra root growth.
Give them a light misting of water.

Lastly, remember to label. Very important! That is,  if you want to remember what's what. If not, throw caution to the wind and look forward to those garden surprises that summer brings. Today I'm using cut up milk cartons. Pop sticks also make great garden labels that have the added benefit of being compostable.


As I was pricking out further seedlings, I came across this little guy below. The pic shows just how amazing seeds are - the seed is cracked open and the stem with leaves is shooting up towards the light, while the long tap root has emerged from underneath to seek out moisture and very soon, nutrients.

Isn't nature truly amazing??
Place the newspaper pots or punnets into a bright, warm, sheltered spot and water regularly (every few days).

Once their second set of leaves form (first true leaves), I'll change their watering to a diluted worm juice solution and increase the frequency.


I placed my pots into the recently cleaned out cold frame in our courtyard which receives the morning sun.

How do you like to start your seeds off?

12 comments:

  1. I hate pricking out or thinning, feels murderous, but putting them into pots like that to give away is a great idea. But I start mine off more individually, one or two carefully spaced seeds to a jiffy or mini pot, as I am a lazy gardener really!

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  2. I was just thinking about what to do with my newly germinated tomato seeds and you have just helped me decide!

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  3. I had planted tomato seeds a couple of weeks ago and left the seed trays in the grow house. We have since had cool (read bloody freezing) weather so they are only poking their little heads up now.
    However, in the raised bed in the grow house that contained the tomatoes last year, lo and behold, I have sooooo many volunteers I don't know what to do with them. I've already pricked out and repotted 33 of them and barely made a dent. So I'm back out there tomorrow to repot more and I'm thinking of the local market and hopefully selling some as "Heritage Pot Luck Tomatoes" as I haven't a clue which is which. But they were all heritage tomatoes. So we'll see how we go.

    Jan

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  4. Thank you. I didn't know you could transplant before the true leaves came in. Neither did I know you could plant them deeper for better roots. There's always more to learn, isn't there. I'll get on to mine this weekend!

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  5. great pricking out lesson, just like we did in the nursery, we used knitting needles instead of a stick though. I still have empty seed trays, little one high maintenance at the moment - might bring them inside and do now. We have tomato volunteers up already.

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  6. my conscious is being 'pricked' by your seedling pricking post because i haven't planted a single seed..i love your little newspaper pots..after first seeing them on an earlier post of yours i made some and planted straight into them..they were a great success..thanks..

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  7. Thanks. This is just what I was planning to do on the weekend with my 50+ tomato seedlings. (gulp!)

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  8. Thank you to all Christine's blogger followers for your concern for her Dad. In this difficult time Christine is a tower of strength to me and it is one of my greatest joys to spend time with my wonderful, talented daughter and her gorgeous family. Oma

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  9. Hi Christine,
    great post because I hate thinning the seedlings. I just feel so sorry for them , throwing them away.
    Hello Oma,
    my best wishes to you and your family, I think lots of good thoughts do go to making a difference and I am glad we have touched you. Yes you do have a talented daughter , there is not a post goes by without me learning something new.

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  10. Super idea! I always seem to destroy so many little roots when I transplant my seedlings but this idea totally solves that problem, so thank you very much :)

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  11. Thankyou all for popping by (including Oma!).

    It's exciting to be starting seeds off again, I love the moment when the seed cracks open and you can catch a glimpse of the tiny shoot breaking apart the soil as it reaches towards the light!

    As functional as my rustic stick is, I do think a knitting needle would work marvelously at 'pricking out'. Great tip!

    Kim, you really touched my heart with your kind words, thankyou :) xx

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  12. As a novice urban gardener, this was a really insightful and useful tutorial - thank you for sharing!

    Blessings,
    This Good Life

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Hi there, so nice of you to stop by! Thanks for sharing your thoughts, I love hearing what you are up to. Christine x

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