September Gardening Notes

PLANNING AND GARDEN JOURNAL

• Refer to your gardening journal to prepare for your fall tasks.
• Make note of how well your annuals performed.
• Make a list of what to order for spring blooming bulbs and place your orders.
• Add photos to help for next year.
• We are entering autumn, time to plan and shop for adding new plants in your landscape.
• Order fruit trees for next year, many nurseries have online preordering.
• Time to start planning and preparing new gardening space for early spring planting.

LANDFILL DIVERSION

• Composting

o   What are Hot and Cold Methods? Link
o   Visit our website for more information. Link
o   Vermiculture – Worm Composting Link

• Grass cycling – See below under “Lawn” section
• Right Plant Right Place – Select the plant for the mature size, climate conditions, sun requirements, and irrigation needs.

WATCH OUT FOR INVASIVES

• Invasive Weeds of Humboldt County 3^rd Edition Link
• Invasive Plant Checklist for California Landscaping Link
• Green Gardening Brochure Link
• CAL-IPC Humboldt Website Link

VEGETABLE GARDENS

• Planting times gleaned from The Humboldt Kitchen Gardener by Eddie Tanner

• Time to sow seeds for coastal areas in September:
• Lettuce, Spinach, Cilantro, Dill – March through late September
• Summer Squash, Cucumbers – April through late June
• Bok Choy, Chinese Cabbage – March through early September
• Radishes, Asian Greens, Arugula – March through late October
• Peas – Greenhouse September through October
• Garlic – September through October
• Oats, Rye – September through October
• Time to sow seed for inland areas:
• Lettuce, Spinach, Cilantro, Dill – mid-August through mid-October
• Radishes, Asian Greens, Arugula – late July through early October
• Peas – Greenhouse mid-September through late October
• Winter Cover Crops – mid-September through late October
• Garlic – mid-September through late October
• Wheat – September through mid-October
• Plant cover crops in vacant space in your vegetable garden. UC Davis Cover Crop Database
• Additional vegetable gardening information can be found on Humboldt/Del Norte Master Gardener website link

 FRUIT AND NUT TREES – Gleaned from UCANR The Home Orchard Publication

• Note: not all fruit/nut trees listed may be suitable to plant for your area. Make sure to select the tree and variety that will do best for your location.

• Fertilize mature trees anytime between mid-August through mid-September – Almonds, Fig, Peach, Nectarine
• Fertilize young trees monthly from April through mid-September - Walnut
• Irrigate to soil depth 18-24 inches every 2-3 weeks - All fruit and nut trees
• Annual Pruning –– Apricots (prune before the onset of winter rains to prevent Eutypa fungus infections), Fig
• Remove fallen nuts – mid September through October – Pistachio
• Aphid control – June through September – Pecan
• Add to your gardening library – UCANR Publication The Home Orchard Link
• Additional fruit and nut tree information can be found on Humboldt/Del Norte Master Gardener website Link

INDOOR PLANTS

• Prune plants that have grown too tall.
• For those houseplants that you have outside, it is time to bring them inside before your evening temperatures start dropping below 50 °F. Make sure to look them over closely as you do not want to bring in insects, slugs, and snails. Take the garden hose and give it a good rinse off. Remove damaged leaves.
• Plants start to slow growth and that is the time to start reducing the frequency of water. Water only when the soil is dry to the touch.
• Feed your plants one time this month instead of each watering.
• Additional indoor plant information can be found on Humboldt/Del Norte Master Gardener website link

LANDSCAPE – ANNUALS, PERENNIALS, GRASSES, FERNS

• For seed saving, let the annuals go to seed, as well as for providing food for wildlife.
• For the colder areas, now until early October is the time to plant new perennials, grasses, and ferns. For USDA zones 7-9 plant September through mid-November.
• Herbaceous peonies – divide and plant September through October.
• Remove seedheads from invasive grasses.
• Weed flower beds.
• Refresh mulch.
• In highly visible areas groom while leaving less visible areas less groomed for nesting beneficial insects. In those lesser visible areas leave patches of bare soil for ground nesters.
• Pinch or cut off spent flowers on annuals to keep them blooming into September.
• Deadhead perennials.
• Herbaceous groundcovers will benefit from light fertilizing this month.
• Fall blooming plants may not develop good blooms if they don't get enough water.
• Continue to fertilize blooming annuals in containers every two weeks.
• Discard dahlias that show virus symptoms. UCIPM Link
• English Ivy is invasive and a nuisance. Rats make their home in ivy ground cover. Now is the time to remove it. It you don't wish to remove it, keep it confined. Article Help with removing English Ivy Link

LANDSCAPE SHRUBS AND TREES

Once you sense autumn weather it is time to plant woody plants. Planting in the fall allows for root growth before spring. UC IPM planting woody plants Link

• Shrubs
• Good time to propagate shrubs– take softwood cuttings.
• If the established plants are not regularly irrigated, give these plants a good soaking so they are hydrated going into the winter season.
• Do not fertilize this month.
• Minimal pruning. Dormant pruning happens in January – February.
• Trees
• Assess tree health if you see any problems contact the Master Gardener Help Desk.
• Some may show signs of stress if they haven't received water all summer.
• Recharge roots for those trees whose soil is dry. This will help them to prepare for the winter.
• Do not fertilize this month.
• Roses
• Clean up fallen leaves. Do not add diseased leaves to compost.
• Stop deadheading to promote dormancy.
• Give your roses a good soaking this month to help them prepare for the winter. They will be more resilient against cold damage.
• Do not fertilize this month.
• Manage or take preventive actions for powdery mildew. UC IPM Link
• Propagation – take rose cuttings this month. UC Davis Publication Link

LAWNS

• USDA Zones 4-6 – bad time to seed a new lawn unless you can water between mid-August through Mid-September for it to establish before winter, otherwise best to wait until spring.
• USDA Zones 7-9 – End of August through September is a good time to overseed.
• Good time to aerate which helps with air and water to move easier. Aerating helps to create stronger grass roots. Water a few times before aerating. Aerating Link
• Overseed this month after core aerating and dethatching. Dethatching Link
• Mow as needed. Consider grasscycling. Mowing Your Lawn and Grasscycling Publication 8006 Link
• Check and repair sprinklers as needed.
• If you haven't been watering regularly, give at least one deep watering this month.
• Use a complete fertilizer. Check schedule for types of grass.  Link to UC IPM When to Fertilize
• The Guide to Healthy Lawns UC IPM Link

LANDSCAPE IRRIGATION

• Adjust watering schedules according to the weather and plants' changing need for water. Check systems for leaks and broken emitters and perform maintenance as needed. Consider upgrading the irrigation system to improve its water efficiency.
• By the end of the month drought stress may be seen.
• Towards the end of the growing season, some plants may benefit by reducing the frequency of irrigation to help plants harden off to prepare for fall and winter.
• Soil that is not irrigated may become hydrophobic which is indicated when it won't absorb water and the water rolls off. In this case, water slowly and in increments. Sometimes a wetting agent can be used to break the surface tension.

IPM – Integrative Pest Management

• Abiotic Disorders – Prevent or manage damage caused by aeration deficit, herbicide, salinity, soil pH, sunburn, wind and too much or little water.

• Ants - Manage around landscape and building foundations, such as using insecticide baits and trunk barriers. UC IPM Link
• Aphids - On small plants, spray a strong stream of water or apply insecticidal oils and soaps. Look for and conserve natural enemies such as predaceous bugs, lacewings, lady beetles, and syrphids. UC IPM Link
• Black sooty mold – Black and oily leaves indicate an infestation of scale or aphids. UC IPM Link
• Borers – Deter by deep watering trees adapted to summer rainfall, e.g., fruit and nut trees. Protect trunks and roots from injury and avoid pruning, except for hazardous tees and certain pest and plants that warrant summer pruning. UC IPM Link
• Citrus - Monitor for damage and pests such as leaf miner. UC IPM Link
• Clean up mummies and old fruit and nuts in and under trees to avoid harboring pests. UC IPM Link
• Codling moth of apple and pear - Bag fruit. Promptly remove infested and dropped fruit. Apply insecticides only if precisely timed. UC IPM Link
• Coast redwood dieback – Check for drought-stress related maladies such as abiotic disorders, bark beetles, fungal diseases, and spider mites. UC IPM Link
• Compost - Turn and keep it moist. UC IPM Link  
• Crane flies – common in Humboldt causing damage to lawns. UC IPM Link
• Cypress, or Seridium canker – Prune dying branches at least 6 inches below any apparent cankers. Irrigate appropriately. Replace severely affected trees. UCIPM Link
• Dampwood termites begin to swarm toward the end of August. These termites are commonly found in cool, humid areas along the coast. They infest moist wood, creating large open galleries where they live and feed. Check your home and other structures for signs of moist wood and termite damage. UC IPM Link
• Nematodes – Nematodes are microscopic, eel-like roundworms. The most troublesome species in the garden are those that live and feed within plant roots most of their lives and those that live freely in the soil and feed on plant roots UC IPM Link
• Powdery mildew – distinguished by gray cover of powdery mildew can be seen on some plants as evenings become cooler and overapplication of nitrogen fertilizer. UC IPM Link
• Root rot - Favored by excessive water and poor drainage. Avoid overirrigation and waterlogged soil. UC IPM Link
• Slugs – August through September is their prime egg producing time. They are light tan round eggs and can be found under a log or mulch. Good idea to remove and toss them away from your garden to be dinner for spiders and black ground beetles. Or just smash those little beasts. UC IPM Pest Link
• Spider mites - Irrigate adequately, mist leaf undersides daily, reduce dustiness, spray horticultural oil. UC IPM Link
• Webworms – The caterpillars chew leaves and form silken tents or webbing on host trees. Their feed causes foliage to turn brown, die, and drop prematurely. UC IPM Link
• Wasps and yellow jackets are both a friend and foe. They can be vicious while being a beneficial insect predator. They are most active during the warmest part of the day. UC IPM Pest Link

EXCELLENT ADDITIONAL RESOURCES

*Get a 10% discount for UCANR books purchased online at UCANR's Book Store. Use promocode PRHUM12.

• Humboldt/Del Norte Master Gardener Website Link
• Humboldt/Del Norte Master Gardener Help Desk Link
• University of California Agriculture and Natural Resources Integrative Pest Management Link
• * University of California Agriculture and Natural Resources Publication - The Home Orchard Link
• * University of California Agriculture and Natural Resources Publication – Pests of the Garden and Small Farm Link
• * University of California Agriculture and Natural Resources Publication – Abiotic Disorders of Landscape Plants Link
• * University of California Agriculture and Natural Resources Publication – Pests of Trees and Shrubs Link
• * University of California Agriculture and Natural Resources Publication – Master Gardener Handbook Link
• * University of California Agriculture and Natural Resources Publication – Healthy Roses Link
  
• The Humboldt Kitchen Gardener, by Eddie Tanner, ISBN: 978-0-615-20900-5 (Out of print, look for used copies)
• Insects of the Pacific Northwest, by Peter and Judy Haggard, ISBN 10: 0881926892 (Out of print, look for used copies)
• Pacific Northwest Insects by Merrill A. Peterson ISBN-10:0914516183
• Month-By-Month Gardening Pacific Northwest, by Christina Pfeiffer with Mary Robson, ISBN-10‏:‎ 1591866669 

Image Credit- Image by Susanne Jutzeler, Schweiz, from Pixabay