Arizona garden in September

September! We’ve almost made it through the long hot summer. The good news — lots to plant this month in the garden. The bad news — the days are still hot. Even so, the mornings and evenings are beginning to cool off, reminding us why we love to live in Arizona!

Gardening in Arizona means there is something to plant or harvest year round. Most vegetables can be grown in Arizona if they are planted at the right time, and for a lot of vegetables, September is the right time. Prepare your Arizona garden in September for fall planting by amending with compost and organic fertilizer.

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Pests in the Arizona garden in September

Unfortunately, the slightly cooler temperatures of September are inviting to pests. It is important to make efforts to prevent pests organically, but not all pests can be prevented. Be on the lookout this month for infestations in the garden. 

Spider mites are a type of arachnid. Relatives of spiders and ticks, they can suck the life out of plants (literally). Prune out large infestations, and spray off with water or neem oil. You may need to treat repeatedly.  Spray plants off with water regularly to prevent future infestations.

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Tecoma plants, yellow bells and bougainvillea often get infested with small caterpillars at this time of year. If the plant is large, it usually survives the infestation without affecting the overall health of the tree. If you decide to treat, here are a few choices: spray off with water, soapy water, neem oil or use BT. When the weather cools a bit, the caterpillars will have moved on. Prune severely infected branches. 

Arizona Garden in September #gardening #garden #arizonagarden

Whiteflies are active in the warm weather of late summer and early fall. Aphids are most active in cooler weather. If you notice infestations of either, try a soapy water treatment, giving particular attention to the undersides of leaves. Spray in the morning and be sure to rinse plants off afterwards. Several treatments are usually necessary. 

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What's growing in the Arizona garden in September?

Arizona Garden in September #gardening #garden #arizonagarden

Peppers are picking back up again. If you did not give them a light prune in August, go ahead and do it in September. Mulch plants with compost and water deeply. 

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September harvest picture: Edamame is finishing up, lots of snake beans, a couple monsoon-planted squash or cucumbers, and some kale

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September is a good time to plant cole crops (Brassica oleracea). These include plants such as kale, Brussel sprouts (pictured here), broccoli, cabbage and cauliflower

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Which flowers are growing in the Arizona garden in September?​

September is a time of change in the annual flower bed. Clear out summer blooming annuals and amend beds well with compost. Once daytime temps are below 100 degrees F., begin planting cool-season annuals from seed and transplants. Consider planting snapdragons, alyssum, lobelia, pansies, geraniums, calendula, nasturtium, bachelors buttons and stock. Water newly-planted annuals each day until they show new growth and are established. 

Arizona Garden in September #gardening #garden #arizonagarden

Blue Daze is an evergreen member of the morning glory family with blue flowers. This low maintenance plant thrives in tree wells or containers.  

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Blackfoot daisy loves hot dry conditions and does well in rocky areas. This low-mounding perennial gets about 2 feet wide and 1 foot high. 

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What's happening with fruit trees in the Arizona garden in September?​

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Lemons are beginning to ripen in September. Skin color is not always an indicator of ripeness, so taste fruit to see when it is ready. Fruit stores best on the tree. The longer the fruit stays on the tree, the sweeter the fruit becomes. Fruit will not ripen once picked. Ripe citrus fruit can be left on the tree for up to 6 months depending on the variety.

Pomegranates will be ready to harvest in October. Remove fallen and infested fruit to keep leaf-footed bugs under control. 

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What's happening with herbs in the Arizona garden in September?​

Basil is going strong. Continue to harvest to keep the basil from going to seed. Try one of my favorite ways to use fresh basil in this recipe

The oregano, mint and other perennial herbs are looking a little haggard. Once temperatures dip below 100 degrees F., trim them back by about 1/3 and feed with organic fertilizer and water well. The herbs should bounce back and look good again soon. 

Arizona garden in September to-do list:

  • Prune summer-damaged perennial herbs back by about 1/3.
  • Fertilize herb and vegetable beds, add compost as well. 
  • Do not prune fruit trees this month. 
  • Fertilize citrus trees, if you didn’t do it in late August. Water citrus deeply this month, before and after fertilizing. 
  • Once temperatures are below 100 degrees F., begin to adjust time between watering citrus and other fruit trees to around twice a month. Water deeply but not as often as in the summer months
  • Clear out summer-blooming annuals and make room for cool-season flowers and annuals. Save seeds from Zinnias. 

What to plant in the Arizona garden in September:

  • Plant seeds for Swiss chard, spinach, turnips, beans, beets, cabbage, celery, cauliflower, cucumbers, kale, lettuce, and peas.
  • Plant transplants of broccoli, cauliflower, Brussel sprouts, and potatoes. 
  • Late in the month, plant garlic, onions and I’itoi onions.
  • Herbs to plant this month: anise, bay, borage, calendula, chamomile, cilantro, dill, fennel, garlic chives, lavendar, parsley, rosemary, sage and thyme.
  • Plant strawberries this month — mulch well and space about 12 inches apart. 
  • Plant spring-flowering perennials this month. 
  • Begin fertilizing roses again this month. Keep up with watering every few days until temperatures cool in October. Once temperatures are below 100 degrees F., prune roses lightly to remove dead or diseased canes.
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