Growing Watermelon

Cucurbitaceae c. lanatus : Cucurbitaceae / the gourd family

Jan F M A M J J A S O N Dec
            S S S S S S
T T             T T T T
P               P P P P

(Best months for growing Watermelon in Australia - sub-tropical regions)

  • S = Plant undercover in seed trays
  • T = Plant out (transplant) seedlings
  • P = Sow seed
  • Grow in seed trays, and plant out in 4-6 weeks. Sow seed at a depth approximately three times the diameter of the seed. Best planted at soil temperatures between 21°C and 35°C. (Show °F/in)
  • Space plants: 60 - 75 cm apart
  • Harvest in 12-17 weeks.
  • Compatible with (can grow beside): Sweetcorn, Sunflowers
  • Avoid growing close to: Potatoes

Your comments and tips

15 Jun 22, Liz (New Zealand - sub-tropical climate)
Seeds saved from hybrids don't usually grow true.
08 Jun 22, Marlow (USA - Zone 9a climate)
I seem to have bottom rot on my watermelons. Two out of 3 are effected. I've read that it's because the soil is lacking calcium. I'll be getting a soil tester tomorrow to check the pH. What would be the best thing to add calcium to the soil? I just don't know if that would work or if I should start new seeds and plant in an area that already has the pH suitable for watermelons...
17 Jun 22, (USA - Zone 4a climate)
Probably too late now but use Epsom Salts - scatter some of this in your soil in future especially where you plant the seeds.
13 Jun 22, Sarah (USA - Zone 9b climate)
Maybe adding eggshells to the soil will help
26 Apr 22, Noelle (USA - Zone 10a climate)
Spacing for vertical watermelon growing? I have a 2x4 bed and planted watermelon on opposite ends on one side (Sugar Baby variety) and one on the center on the opposite side (Crimson) with the goal of having them grow vertically. I only expected three plants total but planted more seeds since these were older seeds. I now have eight watermelon plants that are growing beautifully. I don't want to thin, but I'm sure it's necessary. Any advice on spacing for vertical growth? I've read all sorts of different suggestions online.
28 Mar 23, Martin (USA - Zone 10a climate)
Hey how did those watermelons turn out. I'm thinking about growing rhem vertically
09 Mar 22, Trish Deeter (USA - Zone 10b climate)
What are the best seeds to purchase for Zone 10b, Costa Mesa, Southern part of California near the ocean?
03 Apr 23, Karen Hutchison (USA - Zone 10b climate)
I have had good luck with Klondike
07 Feb 22, Laura g Gatt (Australia - sub-tropical climate)
Hi hope you can help me, I live in Sydney. I have huge Vine of watermelon lots of flowers but no fruit very few bees thanks regards Laura
08 Feb 22, John Mauger (Australia - temperate climate)
Watermelons, cucumbers, squash, and zucchini's all have both male and female flowers on the same vine. For some unexplained reason some plants produce lots of male flowers and few female flowers. The male flowers have a longer spindly stem and the female flowers have an unformed fruit at the base of the flower. If you have female flowers and fruit are not forming it would indicate a lack of pollination by bees or other insects. If you pick some male flowers and remove the petals you can hand pollinate the flowers by putting the male flower, minus the petals, into the female flower to transfer pollen and fertilise the flower. You could use a couple of male flowers with each female flower to ensure that the pollen is ripe. leave a few male flowers on the plant for subsequent flowering. If there are few or no female flowers you can only wait and hope that some appear. Trust this helps.
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