Seeds of Change – A Guide to Potting

This is our fourth growing season of our allotmenteering adventure. We’ve had many highs and lows during these last few years, with some surprising successes and as many abject failures. Some crops have proven themselves easy and reliable (beetroot) while others fail to even show up (carrots).

I think part of the issue we have is down to our soil. We’re on top of a hill, with only a foot or so of soil before you hit limestone bedrock. As a result it’s very stony, making it pretty much impossible to achieve the fine tilth suitable for planting seeds directly into the ground. Larger seeds, and particularly hardy plants, power through, pushing their way out toward sunlight. For others however, it’s an impenetrable barrier, resulting in wasted time and general despondency.

This year however, there’s a new weapon in our arsenal: our greenhouse. Early April was a little too cold to put our seed trays in the greenhouse straight away, with a lingering risk of late frost hanging in the air. Instead we lined our window sills with seed trays, which I can just happily report, have produced a forest of delicate green shoots. Thankfully, they’re now in the process of being shuttled off to the greenhouse to begin their new lives, but here’s a little guide to all things seed related that will hopefully help you as much as they helped us.

Things to plants seeds in:

If you have seed trays, by all means go ahead and use them, but in these days of reuse and general plastic aversion, we’ve been experimenting with some plastic-free and recycled alternatives. Here’s our top 3:

Cardboard tubes
With the recent binge buying of toilet rolls, I can only guess that most people are rolling in leftover cardboard tubes. Don’t throw them away. Instead, consider cutting them into two halves avnd stuffing them full of compost. They make perfect planters for seedlings and can be packed together on a tray for a very eco friendly alternative to plastic trays planters. They also have the benefit of being free draining and the absorbent cardboard helps to keep the compost moist.

Plastic packaging:
You know those nasty little clear plastic tubs that grapes and tomatoes come in? I’ve always hated those guys. But wait, now they finally have a use. Fill ‘em up with compost and you have a nifty little planter for seeds. As a bonus, they normally come with drainage holes too! Packaging for meat can also be used, but you’ll have to make your own holes (and wash them thoroughly to avoid any little shop of horrors-style shenanigans).

Egg cartons
These cardboard beauties come with 6 or 12 ready-made pots just waiting to be filled with seeds.

Types of compost:

Ideally you should use compost that is intended for potting as this is very light and fine grained, allowing seedlings to push their way up through it with ease. However, we’ve had good results with all seed types when using multipurpose compost – just make sure to only lightly cover the seeds and to not compress the compost to maximise your chances of success.


Depending on the size of the seed, you’ll get best results planting several seeds in a single seed pot. Just remember that you’ll need to re-pot them separately later on. By doing this you maximise your chances of at least one seed sprouting successfully.

Pricking out:

If you’ve planted more than one seed to a pot and the sprouting gods are with you, you’ll have multiple little sprouts cohabiting together. But like many house shares, while things start out well enough, over time there will be friction. When they get bigger, your seedlings will start to compete for water and nutrients, so it’s a good idea to give each of them a place of their own – or alternatively, giving the weaker ones the snip if you have more plants than you need (brutal but necessary).

To do this, make sure the compost is moist and using a wooden skewer or stick, gently prise each seedling free. Pull the seedling out gently with your fingers, making sure to hold on to the leaves as the stems are often very delicate. Done right, you should have a tiny, intact seedling, roots and all, ready to be re-potted. Make a little divot in the new pot and tease the roots in with the stick. Push the surrounding compost into the hole and add a little more to ensure the seedling is safely and securely in place. Give them a gentle water and you should hopefully see your seedlings thrive over the next few days.

From greenhouse to ground:

Eventually the day that all proud parents dread will come, and it will be time for your little leafy babies to fly the nest. You should always look at the back of the seed packet for the optimal time to plant outside, but you also need to make sure your plants are large enough to have a fighting chance. Prepare the bed well by breaking it up with a fork and mixing in some compost to help prevent it from clumping together. Water the bed thoroughly and did out a hole big enough to take the plant and the root-riddled compost from its nursery pot. Avoid the urge to press it into place – the healthy plant you’ve raised will be able to take it from here.

When not to pot:

Some things aren’t really worth potting up, and are much easier to just sow directly outside. It’s worth experimenting to see what works for you and your soil, but we’ve found beetroot, chard and lettuce to be especially easier to grow this way, while french beans have been hit or miss and carrots a complete non-starter. You can even help even the odds by using compost to cover your seeds instead of the surrounding soil. This hybrid method might just be the little boost those borderline seeds need to thrive.

So there we are. A crash-course in growing plants from seeds. Let us know how you get on in the comments section and good luck.

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