September In The Garden

"Autumn is a second Spring when every leaf is a flower". - Albert Camus

September is a month when nature goes through seasonal change and transition. Leaves are turning color, the air is noticeably a bit cooler, some birds are starting to migrate and it is also a busy month for most gardeners. 

Saskatoon gardeners are harvesting vegetables and fruit, canning/freezing and cleaning up their vegetable plots.  Later in the month it’s time to plant spring flowering bulbs.

A prairie gardener knows that in September, one must begin to be aware of frost dates in their area.  According to the 2022 Farmer’s Almanac, the first light frost for Saskatoon will be around September 19.  This is just an approximate projection as frost can occur before or after that date!  A light frost is described as 1.7 degrees C to 0 degrees C. If frost is in the forecast, cover plants with frost blankets or old sheets.  Plastic provides poor frost protection and is not recommended.

Now is the time to harvest tomatoes (green or ripe), corn, potatoes, apples, cucumber, squash and the last of the strawberries. Onions can be left on the top of the soil for about a week once you have dug them up. This toughens up the outer layer of skin which protects the onion’s flesh from fungal diseases and bruising.

When cleaning up areas of the vegetable garden that have been harvested, remember to chop up healthy leaves and add to the compost bin. Garbage any diseased plants – do not compost. Spread compost over the clean harvested areas of your veggie garden. I would not dig it in as the compost nutrients will trickle down over time helped along by rain and snow. Do not forget to keep turning the remaining compost in your bins.


September is a great time to plant trees, shrubs and perennials. The soil is warm and with the addition of Mykes or a root start fertilizer the plants will quickly take root before the ground freezes. When planting a leafy tree or shrub at any time of the summer season do not be surprised if the leaves flag or droop after planting. A fully leafed-out tree/shrub relies on the roots to send it water to keep the leaves turgid. A newly planted tree/shrub is busy creating new roots and will not be able to adequately support both roots and leaves at the same time. The tree is not dying and in fall will be shedding those leaves anyway. 

Keep deep watering mature trees and shrubs in September, but do reduce the frequency. Trees and shrubs are entering dormancy for the year and after the leaves fall there is a vastly reduced need for water. After saying that though, do deep water in mid to late October going into freeze up as you want the trees to go into winter with a block of ice around the roots. This helps to keep the roots at a constant temperature, preventing winterkill and provides the tree/shrub with water come spring thaw. Newly planted trees and shrubs should still be watered routinely in the fall as they are putting out new roots in the warm soil.


Do not fertilize trees and shrubs in September. This brings on new growth that will freeze off which stresses the tree/shrub. 

Fall fertilize your lawn from mid to late September. Fall fertilizers help the grass to store the nutrients it needs to energize the grass in spring and create a lush, healthy lawn that keeps out weeds. Most fall fertilizers now do not have to be watered in and children and pets can re-enter the yard immediately after application. Always carefully read the directions on the bag of fertilizer. More is not better! A fall lawn fertilizer will be labelled as such on the front of the fertilizer bag. 

If you haven’t already done so, move your tropical plants inside. On a warm day, wash them off in the shade with a mild dish soap/ water solution. Rinse off the leaves with clear water after a few hours. Isolate them in another room from your indoor tropical plants until you are sure they have not brought in any ‘visitors’. Reduce indoor tropical watering frequency as days are getting shorter. Fertilizing should have stopped mid - August. 

Lift summer flowering bulbs, corms and tubers in late September/October after the leaves have browned and withered. Dig up the plants, remove the brown leaves, clean off the root and store in a cool, dry and dark location inside the house or heated garage. Always garbage any bulbs or tubers that are brown and mushy.

Fall is the time you will find spring flowering bulbs being sold in the garden centre. These include tulips, crocus and daffodils. I usually wait until the end of September to plant these bulbs/corms as the soil is still warm in early September and this encourages unwanted stem growth.


Some helpful tips when planting bulbs:

Choose bulbs that are firm and blemish free.

Always label your bag as to name and color or include the plant tag. There is no way to tell the color of a tulip/daffodil or crocus just by looking at the bulb!

The general rule of thumb regarding planting depth - the depth of the hole should be three times the height of the bulb. 

Tulips and daffodils – the pointed end goes up. Crocus – the depression in the middle of the corm goes up.

Grab a paper bag and shake and bake your bulbs with a powdered fungicide.  Please do this outside; wear gloves and a mask. This step goes a long way to prevent bulb and root rot. 

Include bone meal in the backfill soil and mix into the soil in the bottom of the hole. Do not let the bulbs directly touch the bone meal powder. Follow container directions!

Water deeply once. Spread a shallow layer of compost over the planting area.  


If you do not have fall blooming perennials in your perennial beds, now is the time to revamp those beds!  Fall blooming perennials include Sedums, Rudbeckia or Black-eyed Susan, Echinacea (Coneflower), Zone 3 perennial Grasses, Asters, Helenium, Joe Pye Weed, and Gaillardia.    

Early September is a great time to divide perennial Daylilies, Hosta and Peonies.  Iris and Garlic can be planted in the fall. As cold weather approaches, mulch the garlic with straw. 

Collect and gather seed heads to dry and put out in winter for the birds. Attach a few seed bundles to a friendly scarecrow you made with the kids.  Just leave your perennials and annuals to go to seed; especially sunflower seed heads.  Ornamental grasses will also provide the birds with some seed over the winter.  Another fun project with the kids is to build a fort or shelter out of cornstalks. 

If September is warm, keep watering your annual summer flowering plants.  Snapdragons, marigolds and petunias will continue to bloom, but not with the same vigor as spring. Create fall planters for the front step with dusty miller, pansies, violas, ornamental cabbage and kale.

The intangible gifts of September are many. The weather is usually just right for gardening, hiking,football games, laughing around the campfire and enjoying nature’s ever-changing show. Hopefully you have been taking pictures of your garden all season long. They will be a welcome change in winter as you view them and plan for Spring 2023!

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