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Radishes are one of the quickest of all crops to grow from seed, which makes them ideal for children or impatient gardeners.

From sowing to eating, your young gardener can be harvesting their first radish in as little as six to eight weeks.

Radishes are normally thought of as small and round with a red skin and white flesh however radishes come in many colours including with white, pink or black skin and can be round or long and thin.

Radishes should be crunchy with a slight hint of peppery flavour and are fun to eat straight from the garden or sliced into a salad or sandwich. They are high in antioxidants, fiber, zinc, potassium, vitamins E, A, C, B6, K and other nutrients.

Follow our seven easy steps to successful radish harvest including tips along the way.

How to grow vegetables - radishes. Handy Hints
How to grow vegetables - radishes.

When to plant and location.

When to plant.

Radishes grow year-round in all parts of Australia. Check hardware stores and garden centres for local varieties.

  1. In cold areas sow from spring to autumn.
  2. In warm areas plant from autumn to spring.

Location.

They grow best in full sun (or with light afternoon shade in hotter climates in summer) in soil that holds moisture well.

  • Start from seed sown directly in the garden or a pot.
  • Radishes take from 6-8 weeks from sowing to harvesting and can be used as a fast crop between slower growing vegetables such as onions.
  • Companion plant with carrots and beetroot for best results.

Soil.

Get the soil right to harvest a bumper crop of spicy radishes

Follow our easy steps to soil preparation.

  • Radishes grow in most soils but before sowing, dig over the soil to remove stones, clods or old roots along with weeds, so the root has room to expand. If it’s heavy clay, consider planting in raised garden beds full of compost and manure.
  • To improve the water-holding capacity of the soil work in well-rotted organic matter or apply Seasol Liquid Compost.
  • The pH of the soil should be around 6.0 to 6.8. If it’s too low, add a handful of lime per square metre.
  • Apply Seasol Plant + Soil Booster and mix it into the topsoil.
  • Water in well and if possible, let the soil rest for a week or so.
How to grow vegetables - radishes. Handy Hints
How to grow vegetables - radishes. Handy Hints

Step 1 – Sowing seeds.

  • Grow from seed sown directly in well-prepared, moist soil at a depth of 6mm.
  • Make a furrow in the soil and space seeds around 5-10cm apart. Plant in rows 15cm apart.
  • As seed is very fine, mixing it with sand can help reduce overcrowding. Lightly cover.
  • Water in well with Seasol to help increase seed germination rates. Mix 30mL of concentration per 9 litres of water (standard watering can).

Step 2 – First growth.

  • Seeds will take 5-8 days to germinate depending on temperature. Watch as the tiny leaves come through the soil.
  • Germination may be slower in cold conditions.
  • Protect young seedlings from snails and slugs. Use an environmentally friendly iron based bait, crushed eggshells or wood shavings.
  • Water gently and apply Seasol weekly to help stimulate strong bulb development and healthy growth.

Step 3 – Baby radish seedlings.

  • As the second leaf forms, gently thin overcrowded seedlings to just 5-10cm apart.
  • Excess seedlings can be gently removed and eaten as sprouts.
  • Use scissors to snip excess seedlings off at the base to avoid disturbing the other roots.
  • Apply a liquid fertiliser monthly that is low in nitrogen (less growth) and higher in potassium (root/bulb development) such as PowerFeed PRO SERIES for Roses & Flowers.

Step 4 – Radishes ready for transplant.

  • Transplant your own seedlings when they are 10-15cm long or transplant seedlings from purchased punnet.
  • If planting your own seedlings, plant to a depth of the seedling plug. If planting from purchased punnet, plant to a depth of the punnet.
  • Push the soil firmly around the roots of the seedlings, but don’t push down from the tip as this can compact the soil around the root zone stopping good root development.
  • Water your newly transplanted seedlings in with Seasol to get them over the transplant shock and for strong root/bulb development.

Step 5 – Radish plant growth.

  • Watch your radishes grow over the following weeks and you will see green stem and leaf growth as the tiny root starts to swell.
  • Keep developing plants hand weeded or hoed and well watered so they are actively growing.
  • Mulching around each plant suppresses weeds and helps retain soil moisture.
  • Every 6-8 weeks give repeat applications of Seasol Plant + Soil Booster to produce a bumper crop.
  • Keep an eye on pests and disease that can affect the growth of radishes. Cabbage white fly caterpillars rarely damage radish roots but may chomp on the leafy growth.

Step 6 – Radish root formation.

  • The top of the developing radish will be seen at the base of the leafy stem after several weeks of growth.
  • Mulch with well-rotted manure or compost such as Seasol Super Compost to a depth of 5cm to prevent the soil drying out and to keep the root moist.
  • Check soil moisture regularly. If the soil is too wet, the bulb will rot. If the bulb is too dry, it will crack and spit.
  • Continue to apply PowerFeed PRO SERIES for Roses & Flowers.

Step 7 – Radish harvest.

  • Harvest when roots are of a good size, usually 6-8 weeks from sowing.
  • Radishes are ready to pick when the top part of the round root is seen above the soil. When the bulb reaches around 5cm across, they can be taken out of the ground.
  • Remove the entire plant to harvest the root. Plants left too long quickly become over mature and inedible.
    Store in the crisper section of the fridge for up to three weeks.

Thing to watch for…

If plants are pushed along with good watering and regular fertiliser applications, there’s not much that goes wrong with radish crops.

  • Cabbage white butterfly caterpillars These pests may attack radish leaves but rarely do major damage. To control, squash any that are found feeding on the leaves, or apply an organically friendly caterpillar spray like EarthCare Natural Pyrethrum insect spray. This will go to work immediately to protect your crops.
  • Slugs and snails These pests may damage seedlings or the developing radish. Keep them at bay with an organic, iron-based snail bait.
  • Peppery or woody flavour Radishes become inedible if left too long in the ground before harvest or if allowed to be too dry or starved of nutrients.
How to grow vegetables - radishes. Handy Hints

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