Premium Garden Soil Supply & Installation Northern Beaches

In our coastal climate, I recommend preparing garden beds at least 2-4 weeks before planting, but ideally 6-8 weeks if you can manage it. This gives time for the soil to settle, organic matter to start breaking down, and any amendments to integrate properly.

The timing really depends on when you’re planting. If you’re prepping beds in winter for spring planting, you’ve got time to let everything settle nicely. But if you’re trying to get vegetables in before summer (which is smart in our climate), you might need to work faster.

Here’s something specific to our area – if you’re preparing beds during winter, make sure you’ve got good drainage sorted before our big storm season. I’ve seen beautiful new garden beds turn into mud bogs during those July downpours because the drainage wasn’t thought through properly.

For Northern Beaches gardens, I always start with quality compost – about 30-40% of the mix. Then I add coarse sand for drainage (not fine sand, which just creates concrete), some composted bark for structure, and usually a bit of aged cow manure for slow-release nutrition.

The key thing in our coastal conditions is getting the drainage right while still holding enough moisture for plants. Too much clay and everything drowns in winter. Too much sand and everything dies in summer. The sweet spot for most Northern Beaches gardens is what I call a “coastal loam” – drains well but holds moisture.

You can fill a bed with just quality soil, but here in the Northern Beaches, I usually recommend a layered approach for deeper beds. If you’re going 500mm deep or more, put some coarser drainage material in the bottom 100-150mm, then your quality garden soil on top.

This is especially important for properties in areas like Narrabeen or Collaroy where you might hit clay pan underneath. Without that drainage layer, even the best soil can become waterlogged during our heavy winter rains.

For shallower beds (300mm or less), quality garden soil on its own is usually fine, as long as the existing drainage underneath isn’t terrible.

For our coastal conditions, I recommend minimum 300mm for most plantings, but 400-500mm is better if you can manage it. Vegetables and herbs really need that extra depth because they’re heavy feeders and our sandy base soil just doesn’t provide backup nutrition.

Native plants can often get by with 250-300mm because they’re adapted to tougher conditions, but even they perform better with more soil depth. The extra depth gives you better moisture retention during our hot, dry spells and more root space for plants to establish properly.

For Northern Beaches vegetable gardens, I typically recommend about 1 part quality compost to 2-3 parts good garden soil. So if you’re mixing your own blend, that’s roughly 25-30% compost to 70-75% soil.

Our coastal conditions mean vegetables need extra organic matter to handle the salt air stress and to retain moisture during hot spells. But too much compost (more than about 40%) and you get problems with nitrogen burning and water retention that can cause root rot during our wet periods.

I’ve found this ratio works really well for everything from tomatoes to leafy greens in our climate. The compost provides immediate nutrition and improves soil structure, while the mineral soil component gives stability and prevents the bed from turning into a soggy mess.

For our coastal conditions, I recommend minimum 400mm deep for raised beds, but 500-600mm is even better. The extra depth gives you several advantages in our challenging environment.

First, deeper soil means better moisture retention during our hot, dry periods. Second, it gives you more root space for vegetables and larger plants. Third, and this is important for coastal areas, deeper soil provides better insulation against temperature fluctuations from salt air and coastal winds.