Fall is a great time to evaluate your garden and determine what needs to be corrected, moved, or added. Based on this season’s performance, one can assess the nutrient needs of the soil and landscape plants, determine areas in need of mulch or soil improvement, suppress weeds, and decide in which areas to add or remove plants.

Putting plants in the ground during fall gives them time to grow deep roots so they are able to withstand heat and drought conditions when summer comes again. Cooling air temperatures in fall slows the growth of plants above ground, but the soil remains warm; roots continue to grow until soil temperatures are in the low 50s to upper 40s. Increasing rainfall helps to keep soil moist, but be sure to continue to water regularly until rains are ample and consistent (always water in new plantings regardless of weather or season). It is fine to continue to plant until up to 4-6 weeks before your average first hard frost; I like to get most plants tucked in by mid-November. Things planted close to or after frost may not root much, if at all, but should still fare better than if left in their containers over the winter; consider providing additional protection during extreme winter conditions.

Soil Preparation/Conditioning

  • Add compost annually (1-2 inches deep) to garden beds to improve soil fertility and texture, increase microbe populations, and assist in moisture retention. Do a basic soil test for nutrients and pH; begin making adjustments now so soil is ready for planting by spring (for example, add lime to vegetable gardens or turf areas as needed).
  • Sow cover crop seeds in areas where annual crops are removed to improve the soil and compete with weeds (examples: crimson clover, Austrian pea, fava beans, common vetch).
  • Correct deficiencies, including poor drainage, hard-rock soil, and low nutrition levels. The Water Management team of our landscape division can help with French drains or other drainage techniques
  • This is a great time to start the creation of a new planting bed with sheet mulching or by using the lasagna gardening technique.

Weed Control/Prevention

Dormant weed seeds come alive as fall rains return.

  • Use a layer of weed-seed free compost or mulch (at least 2-4 inches deep) to suppress weeds.
  • Apply a corn gluten product or use Preen as an anti-germination agent in freshly weeded areas where you don’t want new seeds to sprout.

Moving or Dividing Plants

Everyone is happier when not overcrowded! The best tools to use are a cultivating fork or sharp spade and a Hori Hori knife.

  • The most important thing to remember is to give newly moved or divided plants plenty of TLC—regular watering and a little extra mulch in winter, at least for the first year or two.
  • Good rule of thumb: Divide spring-flowering plants in early fall and divide summer and fall bloomers in early spring.

After-Care & Winterization

Even “old” plants are “new” plants once they’ve been moved; young roots need extra protection from extreme temperatures (mulch).

  • If working with deciduous or herbaceous plants that will go dormant for winter, keep moist until dormant and continue to water as they emerge in spring.
  • To speed up the rooting process, use Root Master B-1 after planting.
  • Evergreen plants, especially broad-leafed evergreens, may need to be staked for support until rooted and will need to be kept consistently moist as well as protected from extreme cold temperatures and drying winds (Cloud Cover or MoistureLoc are products that help plants retain their natural moisture levels; they are both sprayed onto the plant’s foliage for protection).
  • Before predicted cold snaps, water all plants well, especially newly planted ones.
  • If using mulch for winterizing purposes, be sure to wait until after the first hard frost so plants have a chance to go dormant; shortly after Thanksgiving is usually a good time. Be sure to leave the area around the crown of plants free of mulch; don’t pile mulch up around the base of plants or against the trunks of trees or shrubs.

What Can Be Planted Now?

  • Spring-flowering bulbs like tulips, daffodils, crocus, hyacinths, and more!
  • All hardy trees and shrubs, perennials, and grasses
  • Cold-hardy color like pansies, dusty miller, coral bells
  • Garlic, shallots, leeks
  • Cold-tolerant edibles such as lettuces, kale, chard, and brassicas (broccoli, cauliflower, Brussels sprouts, cabbage, pak choi)
  • Edible landscape plants like blueberries, fruit trees, and cane berries
  • Herbs
  • Wildflower seeds, grass seed

One of my favorite tools for my vegetable garden is a soil thermometer!

Planting Tips & Techniques

We are lucky to live in an area where it is almost never too cold to plant!

  • Always add some organic matter when planting; use a ratio of one third to half compost to native soil. Dig your hole twice as wide, but no deeper than the pot you are planting from; be sure to keep the plant at the same level in the soil as it was before replanting.
  • Starter fertilizer has essential nutrients that young plants need; many are bone meal-based, which provides plants with the power to grow a healthy root system. We recommend using G&B Starter Fertilizer in every hole you dig!
  • Winter weather can be severe; consider wind gusts and rain patterns when deciding whether or not to stake a tree or shrub for temporary support.
  • To determine if your soil is too wet to plant, squeeze a wad of soil in your hand until it stays in a ball. Poke the soil ball with your finger—if it crumbles to pieces, it is good to plant in; if it stays in a ball when poked, it is too wet to work (you can even do damage to the soil structure if you insist on planting). If drainage is a concern, partially fill planting hole with water to see how well it drains before planting.
  • Some great products to know: G&B Soil Building Conditioner, Malibu Compost (organic and biodynamic), Turface/Profile (improves drainage), G & B Organic Fertilizers