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How to grow tomatoes from seed to harvest

Workshop Legend

Difficulty: Beginner

It’s becoming increasingly popular to grow tomatoes at home. They are easy to grow and can yield a good harvest over a long period, potentially reducing your grocery bills.


Here is a simple guide on growing tomatoes from seed to harvest, including tips on keeping your plants healthy. As this project involves chemicals, please follow all product and safety instructions provided by manufacturers. 


Video Tutorial


Step 1

Plant the seeds.


Fill the seed tray with seed raising mix to just below the tray’s rim. Gently knock the tray to remove any air pockets in the mix. Water the mix lightly. This helps the seeds stay in place.


Now add one seed to each cell. Cover them lightly with vermiculite. Write the seed’s name and the date of planting on a tag and place it in the tray.


Water gently and place the tray in a sunny position.


1.1. Plant the seeds.jpeg


Step 2

Prepare your garden bed.


Select a bed in your garden that receives at least six hours of sun a day and is protected from the wind. To avoid soil-borne pests, tomatoes should not be planted in the same bed or potting mix every year. Rotate to different beds or change potting mix annually.


Mix bagged compost, manure and gypsum into the bed according to the product instructions. Use a fork to blend them to a depth of at least 20cm. Don't forget to wear your gloves and a dust mask. 


Now level the surface with a rake, slightly mounding toward the centre if needed. Water well.


2.1. Prepare the garden bed.jpeg



Step 3

Apply fertiliser to the seeds.


Keep your seedlings moist as they develop but avoid getting them too wet. Apply liquid fertiliser at regular intervals. Refer to the product label for instructions on how to use the fertiliser.


As seedlings develop into plants, move the trays to a sunnier position. Make sure the plants are kept well-watered as they can dry out quickly on hot days.


3.1. Add fertiliser to the seedlings.jpeg



Step 4

Insert plant supports.


Place your preferred plant supports on your bed. Space them out based on the size of your tomato plants. Refer to the seed pack for guidance on spacing. I used double-sided hook-and-loop type ties to support my plants.


If you are planting your tomatoes in pots, fill the pots with soil mix and add some gypsum before inserting the supports.


4.1. Insert plant supports.jpeg



Step 5

Add mulch.


Mulch your beds or pots generously with your chosen straw mulch and thoroughly water the area. This will help the soil retain optimal moisture levels before planting.


Both lucerne and pea straw mulch break down quickly, enriching the soil with valuable organic matter. They also add nitrogen which is essential for strong plant growth.


5.1. Add mulch.jpg


Step 6

Re-plant the seedlings.


Your seedlings are ready to go into a pot or in a bed once they have grown at least two pairs of full-sized "sun" leaves above the first oval baby "seed" leaves. 


Before planting, pull mulch back from your planting spot. Dig a hole deep enough to fit a root ball.


Carefully remove the seedling from its tray cell by gently squeezing the base. Place the seedling in the hole so that the small, first set of “seed” leaves is just below the soil surface.


Backfill the hole with soil and add a suitable fertiliser to the soil around the plant. Now pull the mulch back over the area, ensuring it's kept away from the plant's stem.


Water the newly planted seedling thoroughly with a seaweed tonic like Seasol.


6.1. Sun leaves growing over baby seed leaves.png  6.2. Re-plant the seedlings.jpeg


Step 7

Keep your plants healthy and well-supported.


As the plants grow, keep them well-watered but not too wet. I recommend watering them whenever the soil under the mulch starts to dry.


Use support ties to prop up the plants, especially when they start bearing fruit. If you have support frames, you can also weave the branches through them for extra stability.


Keep a lookout for pests and diseases and treat them with appropriate organic solutions when needed. If you see damage from caterpillars, use a bioinsecticide and remove the damaged fruit. If you are in a fruit fly zone, set up organic traps as soon as the first flowers start appearing. Make sure the baiting fluid is kept topped up.


Prune your plants regularly. Remove any dead or wilting leaves to improve air circulation. Trim any damaged or unruly branches. Apply a suitable seaweed-based fertiliser by following the instructions on the label. Check out the guide How to diagnose a sick plant for handy tips on caring for your plant. 


7.1. Keep your plants well-supported.jpeg  7.2. Avoid pests and diseases.jpg  7.3. Prune your plants regularly.jpeg



Step 8

Enjoy your harvest.


Try to keep the tomatoes on the plants as long as you can. The tastiest fruits are usually the ones that fully ripen on the vine.


If you have to pick the tomatoes early, let them ripen in a warm and well-lit indoor area. Avoid keeping them in the fridge.


8.1. Enjoy your harvest.jpg




  • Seed raising trays, preferably cell-type

  • Seed raising mix

  • Tomato seeds of your choosing

  • Vermiculite

  • Plant tags

  • Bagged quality compost
  • Bagged cow manure
  • Premium potting mix
  • Gypsum
  • Seaweed-based concentrated liquid fertiliser, suitable for both seedlings and plants
  • Mulch, preferably lucerne or pea straw
  • Seaweed-based tonic, like Seasol 1.2L Seaweed Health Tonic Concentrate
  • Bioinsecticide, like Dipel
  • Organic traps, like the Cera Trap
  • Plant supports of your choosing and suitable plant ties.


  • Marker
  • Hand trowel

  • Watering can

  • Hand pruners

  • Garden spade

  • Garden fork

  • Landscape rake

  • Safety gear, including gloves and a dust mask.


1.1. Plant the seeds.jpeg  2.1. Prepare the garden bed.jpeg  3.1. Add fertiliser to the seedlings.jpeg  4.1. Insert plant supports.jpeg  5.1. Add mulch.jpg  6.1. Sun leaves growing over baby seed leaves.png  6.2. Re-plant the seedlings.jpeg  7.1. Keep your plants well-supported.jpeg  7.2. Avoid pests and diseases.jpg  7.3. Prune your plants regularly.jpeg  8.1. Enjoy your harvest.jpg

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