How to plant your Heirloom Seeds

I’ve had a number of requests on what the best way to plant your seeds are. So here’s a quick planting guide.

Most seeds get planted in late winter into cell trays, and then get put into a cold-frame to help them germinate. The reason for this is to ensure that each seed gets the best chance at germinating. Generally we will only plant 5 or maybe ten seeds of each variety and then transplant the resulting seedlings into a bed once they have pushed out two true leaves. The varieties that gain the most from this treatment are tomatoes, peppers and brinjals.

Cell tray numbering
Cell tray numbering

All of these have slower germination times and can take up to 14 or even 21 days to show any movement. They also require at soil temp of at least 17 deg before anything will happen. There are a few tricks that you can use to speed up and ensure better germination, one trick is to cover the seedlings with an old electric blanket or alternatively if you have under floor heating place the seed trays directly onto your floor. Basically what you are trying to do is to give them an even sustained heat so that you can assist with the germination of your seeds. Our Brassicas are also planted into cell trays to give them the best chance at germination.

We use a simple numbering system where each tray is numbered, and then every 5 cells are numbered, this way we can keep track of whats planted in each row with a planting diary. It also give you a good way to track your germination rates.

For larger seeds like pumpkins, melons and cucumbers, you have a few choices, first you can plant them into pots and treat them just like the cell trays or you can wait until the soil has warmed up and plant them straight outside into their beds.

An alternative to pots, using toilet rolls or home made tubes that can be planted with the seedling. The roll biodegrades and transplanting does not set the seedling back.
An alternative to pots, using toilet rolls or home made tubes that can be planted with the seedling. The roll biodegrades and transplanting does not set the seedling back.

Root crops like carrots, beetroot and onions get planted straight into the beds where they are to grow, of the three, onions are the only ones that will forgive you for transplanting them. Carrots and beetroot should not be moved as you are sure to set them back permanently.However you mjst thin them to get the best growth

We plant our corn, peas and beans straight into the garden, and just ensure that they have adequate moisture to assist in germination.

So what’s the best soil to use in your cell trays? We have a mix of commercial germination soil mixed with compost and or vermicompost. It’s up to you to decide on what the best mix is for you, just make sure it’s fine. We find that it’s best to fill the cells just short of top so that when you water (With a fine rose/spray) you don’t wash the soil and the seeds out. Once the seedlings are out it’s good to give them a weekly soaking with either compost tea or ‘worm wee’.

We are very much blessed with great weather in South Africa so it’s not often that we will have bad frost after the 10th of September and in some area’s they don’t even know what frost is. So you can safely start planting out from the beginning of September. Planting out is generally best done in the morning and then following the planting with a good soak. Just make sure that the seedlings have been ‘hardened off’ so they are used to full sun before you transplant, otherwise they are bound to get sun-burnt.

4 thoughts on “How to plant your Heirloom Seeds

  1. Vernon says:

    Dear Sean,

    I have recently embarked on a veggie garden project at my home, and I must say that is coming along nicely. I started off by making a space available on my property, close to the kitchen, and planned out box spaces. I then used old wooden planks that I had laying around and built these boxes. I then lined the sides with waterproof plastic sheets, to minimise wood rot.

    After this used native soil from my garden, mixed with fine grade compost and bonemeal to fill the boxes. I then watered the boxes for 30 minutes for two days, then left them for 24 hours to settle and then planted.

    Some of the boxes I used for seedlings, and some I used to plant seeds into the ground directly. Now, I would like to give the spread of plants per box, so that you can tell me if I should worry about soil contamination or disease in this configuration.

    Box 1 – Large Tomatoes = 8 off
    Box 2 – Green Peppers 8 off and Fennel plant
    Box 3 – Swiss Chard = 7 off
    Box 4 – Onions – 7 off
    Box 5 – Parsley – 8 off
    Box 6 – Basil 6 off and Rocket 6 off
    Box 7 – Marigold plant and Lavender plant
    Box 8 – Small Tomatoes
    Box 9 – Carrots – Seeds
    Box 10 – Red Onion Seeds and Melon Seeds
    Box 11 – Spring Onion Seeds and Cucumber Seeds

    After one week, the seedlings have grown roughly 10 mm, and the Chard especially has shot up almost double. The seeded boxes, containing carrot, red onion, melon, spring onion and cucumber seed, has start showing shoots, approx 3-5mm long.

    I have additional herb seeds to plant into pots and manage then in that way, like.:


    I also have veggie seeds to plant, but would probably be best used to plant on rotation into the boxes.:


    What advise can you give me? Especially in terms of rotation?

    • Sean Freeman says:

      Hi Vernon

      Thanks for your mail. It’s a bit difficult to comment and advise without seeing your setup, however here’s my take on what you have done.

      There is minimal need to worry about contamination with new soil, you are a few years away from any problems. You will generally pick up problems from a few sources, and this will accelerate the problems you may experience.

      1) Infected plants / seedlings from a nursery or friends place. e.g planting infected potatoes from a bag that you were ment to eat, or taking strawberry cuttings from a friend. These are two of the most common infection routes into a vegetable garden.
      2) Poor soil conditions, ie low organic content. This leads to a low biodiversity in the soil and more chance for disease to take hold. A high biodiversity count (I’m talking about micron-organisms) will greatly contribute to the health and disease resistance of your veggies. Look at getting a worm farm/ wormery. ( I have a friend that can assist you in getting your self sorted with a wormery)
      3) Using chemicals on your plants. This goes into the soil and kills of all the gogga’s that look after plant nutrition and soil health and then gives the bad gogga’s a foothold.
      4) Insects, not much you can do about this, except vigilance and the intestinal fortitude to sacrifice a few plants to the insects, they will crowd onto the weaker plant and ‘generally’ leave the healthy ones alone. (Or make a home-brew natural insecticide)
      5) Get a good book on companion planting, there is good evidence that certain plants either contribute or negatively affect others.

      Next, I’d plant all the herbs into freestanding pots and use the bed space for crops, as it sounds like you have limited planting space, try to use the beds for annual/seasonal crops and the herbs which are perennials can go into pots (or straight into the flower beds.)



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