Do you wonder what seasonal gardening tasks should be done month-by-month? Or what seasonal pests to be looking out for? The Humboldt/Del Norte Master Gardener Help Desk Team is providing you with some tasks that will help you maintain and grow beautiful edibles and landscape plants.
GARDEN JOURNALING
- 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.
VEGETABLE GARDENS
- Planting times gleaned from The Humboldt Kitchen Gardener by Eddie Tanner
- Time to sow seeds for coastal areas for August:
o Lettuce, Spinach, Cilantro, Dill – March through late September
o Broccoli, Cabbage, Cauliflower, Kale, Chard, Beets -March through early August
o Bok Choy, Chinese Cabbage – March through early September
o Radishes, Asian Greens, Arugula – March through late October
o Peas – February through early August
o Leeks, Green Onions - February through late August
- Time to sow seed for inland areas:
o Lettuce, Spinach, Cilantro, Dill – mid-August through mid-October
o Broccoli, Cabbage, Cauliflower, Kale, Chard, Beets – late June-early August
o Bok Choy, Chinese Cabbage – late July – late August
o Radishes, Asian Greens, Arugula – late July – early October
o Peas – month of August
o Leeks, Green Onions – February through end of August
- Plant cover crops in vacant space in your vegetable garden. UC Davis Cover Crop Database L
- Additional vegetable gardening information can be found on Humboldt/Del Norte Master Gardener website link
BERRIES AND MISCELLANEOUS FRUITS
- Clean and fertilize strawberry beds and prune raspberries, boysenberries and other cane berries after harvest Link to Growing Berries on the Oregon Coast
FRUIT TREES
- 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, Cherry, Fig, Peach, Nectarine, Pistachio, Plum, Prune, Pluot; between May through August – Pecan
- 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
- Summer pruning any time from June through mid-August– Cherry; June through August – Peach, Nectarine, Plum, Pluot, Prune
- Aphid control – June-September – Pecan
- Codling moth control – Mid March – August – All pome fruits
- 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
- Repot houseplants that have outgrown their containers.
- Closely examine plants – yellowing on lower parts of stems are sometimes common. However, yellowing on new tip growth may be an indication of root rot or other problems.
- Plan for watering of your plants while away on vacation. Find someone to come in at least once a week to water, use a capillary mat, or find an indoor drip system you can put onto a timer.
- Scale back feeding for most foliage plants. Cacti and succulents may benefit from light feeding now through the winter.
- This is a good time to propagate most house plants.
- Additional indoor plant information can be found on Humboldt/Del Norte Master Gardener website link
LANDSCAPE – ANNUALS, PERENNIALS, GRASSES, FERNS
- Divide German irises about every three years.
- 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.
- Lavender when done blooming needs a light shearing of 1/3 of outer foliage. Do not cut back into the wood.
- Deadhead perennials.
- Prune groundcovers and vines as needed.
- 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.
LANDSCAPE SHRUBS AND TREES
- Shrubs
o Good time to propagate shrubs– take softwood cuttings.
o Can be watered less frequently by the end of the month, but don't let them get too dry.
o Do not fertilize this month.
o May benefit by dressing the soil with 2-4” coarse compost or wood mulch – keep mulch away from trunk.
- Trees
o Do not plant trees until fall.
o Assess tree health; if you see any problems contact the Master Gardener Help Desk.
o Some may show signs of stress if they haven't received water all summer.
o Do not fertilize this month.
o May benefit by dressing the soil with 2-4” coarse compost or wood mulch – keep mulch away from trunk.
o Remove stakes from trees planted last year. Roots should be established.
o Check ties that are binding which can cause serious trunk damage.
- Roses
o Clean up fallen leaves. Do not add diseased leaves to compost.
o One last deadheading of spent flowers, then let spent blooms form into rose hips.
o Keep blooming roses irrigated.
o Lightly prune roses to promote fall flowering.
o Roses which have finished blooming, and some shrub roses may get by with 1 deep watering this month.
o Do not fertilize this month.
o May benefit by dressing the soil with 2-4” coarse compost or wood mulch – keep away from trunk.
o Manage or take preventive actions for powdery mildew.
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
- Sharpen lawnmower blades.
- Mow as needed.
- Check and repair sprinklers as needed.
- If you haven't been watering regularly, give at least one deep watering this month.
- Do not fertilize.
- To refresh organic matter, apply ¼ inch of screened compost.
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 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
- Bacterial blast, blight, and canker - Inspect apple, citrus and especially Prunus spp. (e.g., stone fruit). Remove entire affected branches in the summer, making cuts several inches away in healthy wood. UC IPM Link
- Black sooty mold – Black and oily leaves indicate an infestation of scale or aphids. UC IPM Link
- Citrus - Monitor for damage and pests such as leafminer. 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
- Compost - Turn and keep it moist. UC IPM 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 Pest Link
- Mosquitoes - Eliminate standing water e.g., in gutters, drain pipes, and flowerpots. Place Bacillus thuringiensis subspecies israelensis in birdbaths and ponds to selectively kill mosquito larvae. 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. Can find them under a log or mulch. Good idea to remove them 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
- Thrips -Gladiolus are a host for these tiny critters. They can be deadly to gladiolus. UC IPM Pest Link Gladiolus Pests 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
- Humboldt/Del Norte Master Gardener Website https://ucanr.edu/sites/hdnmastergardeners//
- Humboldt/Del Norte Master Gardener Help Desk https://ucanr.edu/sites/hdnmastergardeners/Help_Desk_-_Ask_A_Master_Gardener/
- University of California Agriculture and Natural Resources Integrative Pest Management: http://ipm.ucanr.edu/
- 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
- Month-By-Month Gardening Pacific Northwest, by Christina Pfeiffer with Mary Robson, ISBN-10: 1591866669
- 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