Organic fertilisers for a summer veggie patch, and when to use each

August 27, 2025

Summer vegetables are hungry plants, because a tomato or a zucchini is growing leaves and setting fruit at the same time in the hottest part of the year, and if the soil underneath them is thin they'll tell you about it with pale leaves and not much to pick.

Organic fertilisers come from things that were once alive, like manure or seaweed. Most of them work slowly because the soil life has to break them down before the plant can use them. That's a good thing in a veggie patch, since it feeds steadily rather than all at once. It does mean you put them on before the plant needs them rather than after it's already struggling.

Before you plant, dig in composted manure

The biggest feed a summer bed gets goes in before anything's planted. Dig a good layer of composted cow or chicken manure through the top of the bed a couple of weeks ahead of planting, which gives it time to settle so you're not putting young roots straight into something fresh.

Cow manure is the gentler of the two and does as much for the soil structure as it does for feeding. Chicken manure is a lot richer in nitrogen, so go easier with it.

Blood and bone at planting

Blood and bone is a slow, all round organic feed that's good for leafy crops and for getting a new bed going, and you scatter it at planting and water it in. Keep it well away from natives like banksias and grevilleas because of the phosphorus in it, and rake it into the soil rather than leaving it on top, because dogs love the smell of it.

Pelletised chicken manure through the season

Hungry crops like tomatoes, zucchini, pumpkins and sweet corn appreciate a top up every month or so once they're growing strongly, and pelletised chicken manure is the easy way to do it. Scatter it around the plant rather than against the stem and water it in well.

Follow the rate on the bag, because too much chicken manure will burn roots and more isn't better.

Liquid feeds and seaweed

A liquid feed works faster than anything in a bag because it's already dissolved, so it's handy for a quick lift when plants look tired in the heat. Seasol is a seaweed tonic rather than a fertiliser, and it's good for helping seedlings settle in and for plants coping with stress, while PowerFeed, from the same company, is the one that actually feeds. Plenty of people use the two together through summer and that's totally fine.

Mulch is half the job

Pea straw or lucerne over the top keeps the soil cooler and holds water in, and it breaks down over the season and adds organic matter as it goes, so it's worth thinking of it as part of the feeding plan rather than something separate.

How to tell if you've got it wrong

Pale, yellowing older leaves on a hungry crop usually means it's run short of nitrogen and a feed will help. Lots of lush leaf and very few flowers or fruit on tomatoes usually means the opposite, too much nitrogen, so hold off and let them catch up.

Shop related products

Naturally Good Cow Manure 25L. For digging through the bed before planting.
Brunnings Blood & Bone Based Fertiliser 5kg. A slow feed to scatter at planting.
Brunnings Ultimate Chicken Manure Granules 2.5kg. Pellets for topping up hungry crops.
PowerFeed 600ml. A liquid feed for a quick lift.
Seasol Seaweed Concentrate 600ml. A seaweed tonic for seedlings and stressed plants.

Did you know we also stock pea straw and lucerne in bags and bales in the shop, and they aren't on the website, so give us a ring on (08) 8536 4333 to check what's on the shelf.

The rest of the range is in our garden centre, and if your veggies are sulking, bring a photo or a leaf in and we'll have a look at it with you.