The seedlings start to get crowded in their sprouting containers, the roots start to escape from the bottom holes… It’s time to transplant!
This year, apart from numex suave orange chilli, which I’m still trying to force to sprout, every plant I sowed has sprouted (though not every single seed, obviously!). I’m looking forward to discover all the new plants and chilli varieties I have sown, but never tasted before!
I never know the exact sprouting rate, so luckily I sow more than I need, then I end up with too many seedlings…. (By the way, if you live in Western Switzerland, I would happily share some of my tiny tomato and chilli plants, but they are too fragile to be sent by post. Drop me an email!).
I hope you aren’t bored yet with my seed-to-harvest stories because today I’ll write about what I’ve learnt about transplanting and keeping the seedlings growing.
- Chillies/tomatoes/plants such as mitsuba or shiso that will afterwards end up growing individually (or by two-three): when you see the roots growing well outside of the initial container and/or simply when your seedlings come from seeds sown in groups and get too crowded
- Herbs sown in their final big pot (I did it with chives, dill, coriander and nira, see the photo below) do not have to be transplanted
- As delicately as possible, taking as much of the soil with the seedling as possible and making sure you don’t damage the thin stalks or roots
- If you have several seedlings of the same plant and some look unhealthy or damaged (broken/yellow/missing leaves, strange shape…), discard them.
- If you have several seedlings growing close, separate them even if you transplant them to one pot; this should avoid the roots to get too tangled
- If you have used the moist cotton pad sprouting method (see my previous post), you should use tweezers to delicately place sprouted seeds onto the moist soil, cover with a thin layer of soil, then spray with water
- Make sure your potting soil is moist before placing the seedlings (though not soaking wet), then make a hole (with your finger or a thick stick), deep enough for the seedling’s root to fit (unless the root is strangely long for the plant’s size, then you can delicately bend it), then place the seedling and cover with soil, burying at least the lower part of the stalk; cover with soil and spray with water
- My favourite growing medium is exactly the same as the sowing medium I mentioned in the previous post : good soil+perlite (the whitish spots you can see in my pots); I mix soil with about 20% perlite
- Do not use soil with included fertilizer and don’t fertilize small seedlings
- Reuse the remains of the soil you have used for sowing seeds, it’s a pity to throw it away and it wasn’t “damaged” during the few weeks it was used for sprouting
- The soil should be kept moist but not soaked with water
- If you spray the seedlings, don’t do it when the sun shines (the leaves might get burnt)
How many plants per pot?
- You will read in many gardening sources that seedlings should grow in individual small pots (max. two per pot), then you should repot them into small individual ones, then into bigger, still individual ones,…. I transplant some seedlings by one, some by two or more into the same pot, depending on the pot and seedlings’ size, just making sure their roots don’t get too tangled.
Size and kind of pots
- The smallest and cheapest possible, unless you have lots of space to grow them. If the pots are too big or too deep for the plant (the should be just deep enough for the roots+some of the lower stalk), it will concentrate on growing roots instead of growing the top part; it’ll also be more difficult to keep the humidity level right, i.e. not dry but also not soaking wet
- All the pots should have holes through which the water can flow
TIP : Reuse yogurt tubs! I start washing and collecting (especially small ones) in December, use them in the first transplanting session, then throw them away (thus I don’t have to stock them during the whole year!) and repeat the same the following year. I eat yogurts all the time, anyway.
I need two empty yogurt tubs for each seedlings. I make several holes in the bottom of the first one and place it into the second one, which serves as a “saucer”. Smallest yogurt tubs are perfect for one or two small seedlings!
How to grow the transplanted seddlings? (Supposing you live in a similar climate or colder to mine)
- Where? Indoors or in a heated greenhouse! (Apart from certain exceptions, but even those should be kept protected, even if placed on a sunny balcony, see the last chapter below)
- Light: either under grow lights (they really are a fantastic invention!) or very close to a window; by close I mean almost touching the window and at the same level (put the pots on chairs, on books, shoe boxes, whatever you find)
- – If you have a South-facing, sunny window, make sure the strong hot light doesn’t burn small seedlings (e.g. place a thin slightly transparent fabric on the window)
- – If you have a North-facing window only, you might have a slow growth and leggy seedlings problem (see below)
- – I use West-facing windows and, this year for the first time, grow lamps; this year I experiment with the same plant’s seedlings grown in two environments!
- Temperature and light requirements might vary, so check the information about every single plant you grow; I would generally avoid temperatures below 20°C for all the tiny seedlings.
- Totally normal! Expect to lose some seedlings during the transplanting process; it’s normal there’ll be some loss (hence also my advice to sow more than needed)
- Leggy seedlings are the biggest and most common problem with seeds grown indoors; it simply means the seedlings didn’t have enough light
- If you have a North-facing window only and try to sprout/grow such sun-loving plants as tomatoes or chillies, do buy a special grow bulb! (It’s quite wide, so I recommend also a clip, such as this one, because it’ll probably be difficult to find a “normal” lamp wide enough to install the huge bulb
- If you already have leggy seedlings, they should be buried up to the half of their stalk during the transplanting process
- Slow growth usually also means not enough light or unfit growing medium (for ex. too compact, hence my advice to add perlite to the standard soil) or too low temperatures (check the requirements for each plant)
When to put seedlings outside? (By outside I mean a balcony or a patio, not a garden)
In 99% of gardening advice sources you’ll read “after the last danger of frost”, but this doesn’t apply to a patio or a balcony, where the temperature is a bit higher. Since I use different types of protection covers (plastic mini greenhouses from this year) and can always put back the plants inside in case of frost, I put the plants outside earlier than I would into a real garden….
In short, checking the exact information on every plant’s needs is the most important thing to do, but also checking your growing space’s temperatures (vs. outdoors temperature) and observing weather forecasts in case the plants have to be moved temporarily inside. Be very careful with this step, so that you act in time before losing the seedlings you have obtained with so much effort!
- Most chillies require a minimum of 15°C at night, tomatoes at least 10°C at night, so I will have to repot chillies and tomatoes at least once more, and maybe even trim them, before moving them to a balcony.
- Other plants, such as mitsuba, coriander, Chinese celery or dill, grow happily at lower temperatures, especially under a small plastic greenhouse (though next week for example, the weather forecast announces 0°C at night, so I’ll put them back indoors at least during nighttime!)
- Hardening: whatever the plant, it should first be hardened off (kept outside first only during the daytime) for about a week, so that it gets used to sun, wind etc…
A quick peak at my messy tiny outside window sill (I don’t know how people manage to grow beautiful instagrammable plants outside! Mine always look dirty; some pots look awful even thoroughly washed after the first season and even spotless pots become dirty in a couple of days!):
Let’s sump up: once you have transplanted, all you need is well-draining soil, good light, warm temperature and patience!