A Deep Dive Into Citrus Containers
Garden book author and citrus expert Lance Walheim, is a big proponent of growing citrus trees in containers. We discuss his techniques in today’s podcast, along with shameless plugs for his new book, “Citrus: A Gardeners’ & Fruit Lovers’ Guide [https://walheimpress.com/].”
For those of you in a hurry, here are some of the important points we touch on in the podcast:
Choose compact citrus varieties for containers — Meyer lemon, kumquat, calamondin, and Bearss limes are ideal; avoid vigorous types like Lisbon lemon or grapefruit, which will quickly outgrow most pots.
Upgrade container size gradually When repotting, go up only one size at a time (e.g., sleeve → 10-gallon → 15-gallon → half barrel). Transplanting immediately from the nursery pot to an oversized container can hold excess moisture around the roots and can cause rot.
Prioritize drainage above everything else Check that your container has multiple drain holes (at least 4–5 for a half barrel, ½-inch diameter or larger), and drill additional side holes if needed.
Raise your container off the ground Set pots on bricks, boards, or a furniture dolly to keep drain holes clear, prevent roots escaping into the native soil, and allow the bottom of the pot to dry properly. If setting pots in catch dishes, don’t let them hold standing water.
Use quality commercial potting mix, not backyard soil Garden soil may compact easily, drain poorly, and can introduce pathogens. Consider amending potting mix with perlite, builder’s sand, or pumice for improved aeration, keeping in mind this will cause it to dry out faster.
Avoid dark-colored pots in hot climates Black plastic containers in full sun can heat soil to 120–130°F on warm days, killing roots. Use fabric pots, light-colored containers, or nest a dark pot inside a larger one filled with mulch for insulation. Surrounding the citrus pot with other pots can help keep the citrus roots cooler.
Fertilize consistently and at a diluted strength Use a liquid or water-soluble citrus fertilizer [https://www.amazon.com/dp/B0C73S6Q23?pd_rd_i=B0C73S6Q23&pd_rd_w=SDjyC&content-id=amzn1.sym.4a7f44df-467c-45a1-af5f-91661a6df2f9&pf_rd_p=4a7f44df-467c-45a1-af5f-91661a6df2f9&pf_rd_r=W1XH9DC37YCT2J0V0BBD&pd_rd_wg=p0ths&pd_rd_r=a4720ba6-1743-4478-accf-6d3fea8823b9&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWwy&th=1&linkCode=ll2&tag=getgrowingwit-20&linkId=65774aa750316882bbd43ff7694475ef&language=en_US&ref_=as_li_ss_tl] every two to four weeks. Make sure it contains not just nitrogen but also phosphorus, potassium, and micronutrients like iron, zinc, and manganese.
Leach the soil every one to two months Run water slowly through the entire pot multiple times to flush out salt buildup. A white mineral ring around the pot is a sign salts have accumulated.
Use a moisture meter to check watering needs Finger-testing the surface is unreliable in root-bound pots; a moisture meter tells you conditions 12 inches down where it matters.
Mulch the top of the container A thin layer of bark chips or compost slows moisture loss and protects surface roots. Keep mulch away from the trunk.
Transition plants indoors and outdoors gradually Over one to two weeks, move the pot into progressively shadier spots before bringing it inside, and reverse the process in spring. Expect some leaf drop indoors; a bloom cycle usually follows.
Treat for pests before moving indoors Apply Neem oil [https://www.amazon.com/s?k=neem+oil+spray+for+plants&i=industrial&crid=3PMLOHKTRCHVP&sprefix=neem+oil%2Cindustrial%2C168&linkCode=ll2&tag=getgrowingwit-20&linkId=8c081c5cc13cbe5015ae728b24d540fd&language=en_US&ref_=as_li_ss_tl] or Spinosad [https://www.amazon.com/s?k=spinosad&i=industrial&crid=1SW2BTTWAN2DC&sprefix=Spin%2Cindustrial%2C177&linkCode=ll2&tag=getgrowingwit-20&linkId=b55e0251b92c1225aaf3dd871bbda717&language=en_US&ref_=as_li_ss_tl] before bringing the tree inside to prevent scale or whiteflies from establishing. Avoid applying oil when temperatures are above 85–90°F.
Prune to maintain size and airflow Keep the tree’s center open for air circulation, remove crossing branches, and cut back vigorous shoots. Do major work (including root pruning, if necessary) in winter, the least stressful time.
Look for Flying Dragon rootstock if you want a true dwarf This trifoliate orange rootstock keeps trees to 5–6 feet and is well-suited to long-term container growing, though it can be hard to find.
Buy only from reputable nurseries Asian citrus psyllid and HLB disease [https://www.aphis.usda.gov/plant-pests-diseases/citrus-diseases/citrus-greening-and-asian-citrus-psyllid] have spread to all major citrus states. Purchasing certified trees (rather than propagating cuttings from friends) is the safest way to avoid bringing home an infestation.
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