For pumpkin seeds to germinate and pumpkin seedlings to flourish they need to be planted in well drained warm soil. One of the best ways to do this is plant them using the mound method. This page explains how to plant pumpkins using the mound method and its variant, the brick mound method.
Plant pumpkins after the threat of frost has passed. They can be started a little earlier with the use of cloches, plastic covers, or tree guards, however the advantage is negligible.
When the threat of frost has passed depends on the climate zone your garden is in as well as local climate variations within that zone. As there is a wide climate disparity even within zones it is best to seek advice from experienced vegetable gardeners in your local area as to when you can safely plant. Below are the recommended pumpkin planting times for the climate zones for South Eastern Australia. The Ballarat & District zone being a more accurate subset of the Cold Mountainous zone.
Pumpkin planting guides comparison chart for South Eastern Australia. To download a printable version of the chart, click HERE.
Pumpkins can be planted up to three weeks before the risk of frost has passed, however the advantage is negligible. These pumpkin seedlings are being protected by tree guards, though you can also use cloches and temporary polytunnels.
The mound method involves building a mound of soil about 90 cm wide and 15 to 20 cm high which pumpkin seeds or seedlings can be planted in.
When soil is mounded up it drains better than soil at ground level. It is also warmer due to the soil being more exposed to sunlight. Nothing kills germinating pumpkin seeds quicker than cold sodden soil.
The advantages of the mound planting method.
As most mature pumpkin plants need a minimum of two square metres of space it is best to site pumpkin mounds in a place where the pumpkins can spread, next to a lawn is ideal. Though it is useful to move the mounds around from year to year to ensure that pumpkins are not planted in the same place in consecutive years.
- DIG A HOLE APPROXIMATELY 90CM WIDE AND 30 CM DEEP AT THE CENTRE
- FILL THE BOTTOM WITH COMPOST AND ANIMAL MANURE TO A DEPTH OF 15 TO 20 CM
- FILL THE HOLE WITH THE EXCAVATED SOIL TO A HEIGHT OF ABOUT 15 TO 20 CM ABOVE GROUND LEVEL
Extra soil may be needed to get the mound to the right height. The soil can be partially mixed with the compost below and a bit and a extra compost and manure can also be added to the mounded soil above ground. - PLANT TWO LOTS OF 3 TO 4 SEEDS AT TWO POINTS ON THE MOUND
At each point the seeds should be planted about 5cm apart in a triangulated pattern. Seedlings can be planted in place of seeds, though as pumpkin seedlings react badly to having their roots disturbed it is best to grow them in single cell seedling trays.
The ground around the mound can be covered with mulch but do not put mulch on the mound itself as mulch insulates the soil below it from the sun’s rays. For more information of the properties of mulch see Advantages And Disadvantages Of Mulching Vegetable Beds. - UNLESS THE SOIL IS VERY DRY DO NOT WATER THE SEEDS UNTIL THE SHOOTS BEGIN TO SHOW
- GRADUALLY THIN OUT THE SEEDLINGS TO THE TWO STRONGEST PLANTS
Dig a hole approximately 90cm wide and 30 cm deep at the centre and fill the bottom with compost and animal manure to a depth of 15 to 20 cm.
Fill the hole to a height of about 15 to 20 cm above the ground level.
Plant two lots of 3 to 4 seeds at two points on the mound. At each point the seeds should be planted about 5cm apart in a triangulated pattern. An alternative is to plant two seedlings, preferably grown in single cell seedling trays as pumpkin seedlings react badly to having their roots disturbed.
Seedlings grown in single cell seedling trays. Seedlings grown in such trays keep their root structures much more intact when being transplanted than seedlings grown in communal punnets. Pumpkin seedlings react badly if their roots are disturbed when transplanted.
The brick mound method involves placing bricks around the edge of the mound as support for the mound and to offer extra warmth. It is the method that I prefer to use for growing pumpkins.
The problem with the mound method is that heavy rain can wash parts of the mound away and when being watered much of the water will flow down the sides of the mound and away from the growing seedlings.
Placing bricks around the edge of the mound helps keep the shape of the mound and allows the top of it to be leveled. Water is less likely to run off level ground.
The bricks also act as heat sinks by absorbing heat during the day and giving it off slowly at night when the air temperature drops. This heat sink keeps the microclimate of the mound just that little bit warmer at night.
- BUILD UP A MOUND AS PER THE INSTRUCTIONS ABOVE FOR BUILDING A MOUND
- PLACE 6 TO 8 BRICKS AROUND THE SIDES OF THE MOUNT ON A SLIGHT ANGLE
Partially push the bricks into the soil but leave the outside slope of the bricks exposed to sunlight. - FLATTEN THE TOP OF THE MOUND SO THAT ITS SURFACE SITS JUST BELOW THE INSIDE TOPS OF THE BRICKS
- PLANT AS PER THE PLANTING INSTRUCTIONS ABOVE
Illustration of a brick mound profile.
Brick mound planted out with two pumpkin seedlings. The pale material is a combination of eggshells and sand.
These pumpkin seedlings were grown from six seeds then gradually thinned out to the two strongest plant.
A shovelful of sand can be added when building up the mound to make the soil more friable. This is especially useful if the soil is heavy. The more friable the soil the better the drainage. Sand can also be sprinkled on top as it absorbs heat more readily than soil (remember how hot sand at the beach feels under foot in summer), though don’t sprinkle too much as it can form a hard crust if too thick.
In place of compost and manure you can use fish guts and heads (if you are a fisherman) or a chicken carcass. Pumpkin plants are heavy feeders and will readily absorb such a concentrated dose of protein compost as fish guts or chicken carcasses provide. Some of the best pumpkin crops I have grown were fertilised with chicken carcasses.
