- Sowing in a square in your garden box
- Thinning your seedlings: what, why, and how
- Pre-sprouting snow peas, winter peas, and sugar snaps
- How to pre-sow tomatoes indoors
- Pre-sowing courgettes, cucumbers and pumpkins
- Afharden van zaailingen
- How long do your seeds stay good?
- Are your old seeds still good?
- Harvesting seeds yourself
- How do you take care of pre-sown plants?
- Sowing in a square in your garden box
- Thinning your seedlings: what, why, and how
- Pre-sprouting snow peas, winter peas, and sugar snaps
- How to pre-sow tomatoes indoors
- Pre-sowing courgettes, cucumbers and pumpkins
- Afharden van zaailingen
- How long do your seeds stay good?
- Are your old seeds still good?
- Harvesting seeds yourself
- How do you take care of pre-sown plants?
How to pre-sow tomatoes indoors
Want to grow your own summer vegetables? Then pre-sowing indoors is the way to go. You germinate the seeds inside and move the plants outside once they are strong enough.
You will need MM-Airpots, vermiculite, and MM-Mix. This gives tomatoes and other summer vegetables a much stronger start than ordinary pots and potting compost.
You will need MM-Airpots, vermiculite, and MM-Mix. This gives tomatoes and other summer vegetables a much stronger start than ordinary pots and potting compost.
What is pre-sowing you ask?
Most seeds can be sown straight into your garden box. They germinate, seedlings come up, and your plants grow big and strong.
When you pre-sow, you sow indoors.
Your seedlings grow in a greenhouse or on the windowsill. You give them just the right amount of light, nutrients, and warmth. When they're ready, you'll transfer them to your garden.
This page takes you through pre-sowing using MM-Airpots and a mixture of fine vermiculite and MM-Mix.
This works way better than just using soil or vermiculite in an ordinary pot. Also, it’s fast and easy to do.
Note: the photos almost all show the older MM seed-starting mix, but the steps are almost the same with the MM coconut seed-starting mix. As soon as we have all the photos for that version, we will make a separate page for it. For now, this will do.
The older seed-starting mix is the same as MM-Mix, but with half the nutrients and sieved more finely. So it contains compost and fibres from peat, coconut, and wood. Each bag contains 5 litres of ready-to-use seed-starting mix.
This mix needs to be made properly moist before you sow. To keep it from drying out too quickly, cover the pot with a little household film and an elastic band after sowing. As soon as the seedling has come up, remove the cover again.
This mix needs to be made properly moist before you sow. To keep it from drying out too quickly, cover the pot with a little household film and an elastic band after sowing. As soon as the seedling has come up, remove the cover again.
You also need to keep an eye on the moisture level and water from above when needed. Once this mix dries out, it can be quite difficult to get it to take up water again. But do not make it too wet either, because then the air disappears from the mix.
The new seed-starting mix consists of pure coconut fibre. You receive it as a compressed block. Add water so it swells up, and because coconut contains no nutrients, add 1 tablespoon of MM plant food. After that you have 6 litres of seed-starting mix.
The new seed-starting mix consists of pure coconut fibre. You receive it as a compressed block. Add water so it swells up, and because coconut contains no nutrients, add 1 tablespoon of MM plant food. After that you have 6 litres of seed-starting mix.
You do not need to make this mix nearly as wet as the other one: the fibres hold moisture very well. You also do not need to cover the pot with film after sowing. If the mix later becomes a little dry, pour a little water at the base of the pot. The fibres draw the moisture up very easily.
Another advantage is that this mix is not attractive to fungus gnats at all. That is because it contains no organic material for the larvae to live on, so they do not lay eggs in it.
And finally: coconut mix does not make your hands dirty. A small detail, but a very nice one.
Tomatoes and other summer vegetables take months to produce fruit. And even then, only if the weather is warm enough.
Before that, they also need warmth to germinate and grow. Here in the Netherlands, the weather only gets warm enough around mid-May. But if you sow seeds directly into your garden boxes then, you've started too late. Four months later the days get shorter and cooler. You'll need a lot of luck to harvest ripe tomatoes in time.
So: that's why you pre-sow your tomatoes indoors from late March to mid-April. If you move the plants into your garden boxes at the end of May, you'll pick your first tomatoes by the end of July and continue through mid-October.
Zucchinis, pumpkins, and cucumbers grow faster, but they also need a lot of warmth early on. That's why you pre-sow them indoors too, but you can start later: from late April to late May. Their seeds are much larger, so the process is a little different from tomatoes.
Besides summer vegetables, we pre-sow a few other varieties indoors too. But they do not need to stay inside for nearly as long, and you move them outside quite quickly.
We use this short pre-sowing method for African marigolds, bush basil, and liquorice mint. Mainly because they germinate better at higher temperatures and are extra vulnerable while the plants are still small, for example to slugs.
The same goes for sunflowers: slugs love the young plants. But because they grow large quickly, we sow them straight into a larger airpot.
We also recommend it for our seeds in clay pellets, such as Crystal lettuce, Crispy, Batavia, red butterhead lettuce, and oak leaf lettuce. These varieties grow very large and eventually fill a whole square, but before that happens you can use the square for something else first.
If you only have a few squares, you can also pre-sow and grow many other vegetables in small airpots. By the time you have space again, you can plant them in the square and harvest earlier than if you only sowed them then. Handy for baby broccoli, Chinese chives, or dino kale.
But note: pre-sowing does not work for varieties that do not cope with transplanting, such as carrots or beets.
We use this short pre-sowing method for African marigolds, bush basil, and liquorice mint. Mainly because they germinate better at higher temperatures and are extra vulnerable while the plants are still small, for example to slugs.
The same goes for sunflowers: slugs love the young plants. But because they grow large quickly, we sow them straight into a larger airpot.
We also recommend it for our seeds in clay pellets, such as Crystal lettuce, Crispy, Batavia, red butterhead lettuce, and oak leaf lettuce. These varieties grow very large and eventually fill a whole square, but before that happens you can use the square for something else first.
If you only have a few squares, you can also pre-sow and grow many other vegetables in small airpots. By the time you have space again, you can plant them in the square and harvest earlier than if you only sowed them then. Handy for baby broccoli, Chinese chives, or dino kale.
But note: pre-sowing does not work for varieties that do not cope with transplanting, such as carrots or beets.
What do you need to pre-sow?
You only need a few things:
- fine pre-sowing vermiculite
- MM-Mix
- MM-Airpots
- seeds: for example, cherry tomato, yellowmato, or bush tomato.
- a mixing bowl
- water
- smaller bowls or saucers
Here's how you do it:
Step 1: In the mixing bowl, combine 1 part MM-Vermiculite and 1 part MM-Mix.
Step 3: Fill the MM-Airpots with your new mixture. Press it down gently with the rounded side of a spoon.
Step 4: Poke a hole in the middle of the air pot up to 1 cm deep.
Step 5: Cut open the seed bag and place 1 seed in the hole. Then gently cover it with some of the vermiculite-mixture.
(Our tomato seeds aren't cheap, so only sow 1 seed per pot. For other seeds, you can use 2 or 3).
(Our tomato seeds aren't cheap, so only sow 1 seed per pot. For other seeds, you can use 2 or 3).
Step 5:
If you are using the older seed-starting mix, carefully add a little more water, cover the pot with a piece of clear household film, and secure it with an elastic band. This keeps the seed-starting mix from drying out too quickly.
If you are using the coconut seed-starting mix, you can skip the watering and covering in this step.
If you are using the older seed-starting mix, carefully add a little more water, cover the pot with a piece of clear household film, and secure it with an elastic band. This keeps the seed-starting mix from drying out too quickly.
If you are using the coconut seed-starting mix, you can skip the watering and covering in this step.
Step 6: Put your MM-Airpot in a bowl or dish and leave it in a warm place.
If you're sowing different types of tomatoes, label them right away.
If you're sowing different types of tomatoes, label them right away.
I like to sow 2x as many plants as I'll need later. So if I want 2 tall tomato plants, I'll germinate 4.
If one doesn't sprout, or if something goes wrong during the process, then at least I have a backup.
Many gardeners germinate a whole bunch at once. I'm not into that. You have to keep them all safe and happy indoors until they're strong enough to be moved outside and you also have to find space for them on the windowsill. My windowsills aren't that big.
After all that, you'll end up with too many plants. You either have to give them away or throw them away. And no one wants to put good plants in the trash.
If one doesn't sprout, or if something goes wrong during the process, then at least I have a backup.
Many gardeners germinate a whole bunch at once. I'm not into that. You have to keep them all safe and happy indoors until they're strong enough to be moved outside and you also have to find space for them on the windowsill. My windowsills aren't that big.
After all that, you'll end up with too many plants. You either have to give them away or throw them away. And no one wants to put good plants in the trash.
So, what's next?
After about a week the first seedlings will emerge. It's automatic, they just show up one day. You don't have to do anything except check if the mixture is still moist. You should check regularly because seeds won't germinate without moisture.
As soon as you see seedlings coming up, put the air pots somewhere that gets the most light, but won't get too warm.
Give the pots a quarter turn every day. This stops the seedlings from growing crooked. And again, keep the vermiculite mixture moist.
As soon as you see seedlings coming up, put the air pots somewhere that gets the most light, but won't get too warm.
Give the pots a quarter turn every day. This stops the seedlings from growing crooked. And again, keep the vermiculite mixture moist.
Put the pots in the brightest place you have, but preferably not somewhere too warm.
Keep the mix moist and turn the pots a quarter turn every day. This stops the seedlings from growing crooked.
Keep the mix moist and turn the pots a quarter turn every day. This stops the seedlings from growing crooked.
Windowsill care
Caring for your plants on the windowsill actually is kind of tricky. They want lots of light, but can't get too warm: that's important. So full sun, but not warmer than 20°C, preferably a little cooler.
Keep giving them a quarter turn every day and keep the mixture moist.
Keep giving them a quarter turn every day and keep the mixture moist.
Repotting, hardening off and moving out
At the end of April, transfer your plants to a larger pot full of MM-Mix. No vermiculite this time. A bigger pot gives your plant more room for its roots, so they'll continue to grow.
Once the end of May rolls around, let the plants get used to the outside. Start with an hour and then let them out a little longer every day. This is called hardening off.
After a few days, you'll move the most beautiful plant into its new home.
Once the end of May rolls around, let the plants get used to the outside. Start with an hour and then let them out a little longer every day. This is called hardening off.
After a few days, you'll move the most beautiful plant into its new home.
In the second half of May, let the plants get used to outdoor air, a little longer each day. This is called hardening off.
Once you have done that, plant the strongest-looking plants outside in your garden box.
The app helps you step by step
Alright. So, that was a lot. But you don't have to remember it all.
Each step is written out and illustrated in the app. It also gives you the right instructions at the right time.
Each step is written out and illustrated in the app. It also gives you the right instructions at the right time.
From starting your seeds to removing the plant at the end of the season. And everything in between.
With the app, you pretty much can't go wrong.
It's amazing, isn't it? You can grow so many tomatoes from just 1 tiny seed.
With the app, you pretty much can't go wrong.
It's amazing, isn't it? You can grow so many tomatoes from just 1 tiny seed.
What about the other varieties?
Cucumbers, pumpkins, and zucchinis also need to be pre-sown indoors, but much later: from late April to late May.
Because the seeds of these varieties are much larger, you germinate them first and only then put the seeds into the seed-starting mix. Use a larger airpot straight away, because these seedlings grow quickly and get big.
Because the seeds of these varieties are much larger, you germinate them first and only then put the seeds into the seed-starting mix. Use a larger airpot straight away, because these seedlings grow quickly and get big.
For other vegetables, herbs, and flowers, such as leaf lettuce, bush basil, and African marigolds, you usually use small pots.
Ready to pre-sow?
The seeds, air pots, MM-Mix, and pre-sow vermiculite are in the shop. The rest you've already got 🙂
Have fun!
PS: Why do seedlings grow better in MM-Airpots than in regular pots?
Okay, so in regular pots, roots keep growing along the sides of the pot. They're so busy growing in endless circles, they don't absorb as many nutrients.
With the MM-Airpot it's different. These net pots have openings on the sides:
With the MM-Airpot it's different. These net pots have openings on the sides:
If a root comes too close to the side of an MM-Airpot, it stops growing. That's called air pruning.
Instead of the roots getting longer and growing in circles, the plant will then produce new roots over and over again. The result is a strong root system with lots of young and healthy roots that absorb air, nutrients, and moisture.
Instead of the roots getting longer and growing in circles, the plant will then produce new roots over and over again. The result is a strong root system with lots of young and healthy roots that absorb air, nutrients, and moisture.
Your plants will grow faster and become stronger.
On top of that, you don't need to repot them as often. You'll also have less trouble transferring to your vegetable garden box or MM-Mini outside.
On top of that, you don't need to repot them as often. You'll also have less trouble transferring to your vegetable garden box or MM-Mini outside.
We sell 2 sizes of pots: the smaller airpots for the first stage, and the larger airpots for when you transplant tomatoes into mix only. Cucumbers, zucchinis, and pumpkins are sown straight into the larger size.
(Pre-)sowing
- Sowing in a square in your garden box
- Thinning your seedlings: what, why, and how
- Pre-sprouting snow peas, winter peas, and sugar snaps
- How to pre-sow tomatoes indoors
- Pre-sowing courgettes, cucumbers and pumpkins
- Afharden van zaailingen
- How long do your seeds stay good?
- Are your old seeds still good?
- Harvesting seeds yourself
- How do you take care of pre-sown plants?