Trouble Shooting Potted Patio Plants

We spend an awful lot of time talking about the in-ground problems that plants experience and focusing on diseases and insects of these plants, but containerized plantings have often a unique set of issues.Below are some common issues that can be encountered, with some tips on how to correct them.

You may be able to proactively recognize and correct some of the issues you may have been experiencing—and additionally evaluate those permanent containerized plantings or new edible landscape containers.

• Pot bound roots growing through drainage hole (may also see roots appearing on surface). If this happens for small or medium plants, repot them. If plants too large to easily do this, loosen surface soil and remove top two inches.Add fresh soil to replace the 2 inches you removed.
• Sudden death of seedlings in container. This may be due to pots with no drainage, or damping off or root rots.
• Sudden yellowing of leaves, leaf drop: This can be caused by sudden temperature change; may also be a sign of root rot.
• Leaves turn dull green to yellow and bottom leaves drop off, new leaves are weak and stunted.This may be a potential nutrient deficiency.Containerized plants need to be fed lightly and frequently due to porous media and frequent watering.Change fertility practices and step up the number and frequency of fertilizations, but with lower quantities of fertilizer.
• Top leaves stunted. Rapid growth but no maturity means too heavy a hand with the water soluble fertilizer delivered in a single dose so the part that was absorbed causes the spurt but the rest washes through so there is nothing to sustain the spurt.This can also result in excess salts, and salts can cause problems such as yellowing and marginal burns…leach to wash them through:
• Leaf tips turn brown. First look to see if leaves and stems appear to be broken or bent… if so, this indicates physical damage and bruising which can result in disruption of food and water conducting pipes.Brown tips with yellowing leaves are also a strong indicator of pot bound plants or root rot so check drainage and roots.Trim browned areas.
• Tall, spindly stems with pale leaves. If plant seems to be leaning in one direction or another this can be an indicator of insufficient light.Trim branches back that hang over container or move container so more sunlight is achieved.You can also install a decorative landscape mirror to increase the amount of reflected light.When growth begins to normalize you can pinch or trim back the leggy stems to make plants even more bushy.
• Brown or yellow opaque “window panes”. In certain plants these spots, very different looking from disease spots, are caused by excess sun exposure… they literally have a sun burn.Peppers, for example, may have patches on the fruit like this (called sunscald).Bark can also develop this problem, especially apples and mountain ash on a south or southwestern exposure.Move the plants or plan for other plants or physical barriers to be placed nearby as a screen.Heavy pruning during water stress can also increase plant susceptibility to sunburn.
• Wilting or curling of leaf edges. Insufficient water, excess heat, excess fertilizer (salts), low humidity, or a combination may lead to this condition.Leaves that display this symptom may then become brittle and/or develop brown spots followed by leaf drop.Humidity is easily increased by your containers on a shallow tray filled with pebbles and water to the top of the tray.If it is very hot, even a well-watered plant may not be able to keep up with water demands midday and will visibly wilt only to recover as the temperatures drop and the sun moves later in the day.
• Yellowing of cactus and succulents. Yeah, they don’t need much water but when you underwater either of these you may notice that they literally turn pale and begin to yellow.Try the pebble tray for these types of plants as well.
• Lower leaves begin to yellow. Transplant shock is a common cause of yellowing on lower leaves and even leaf drop of lower leaves.However, if leaf yellowing and drop is accompanied by stem softening plus boggy media, drainage/over watering may be affecting the plant.You can try drying out the container for several days to see if this improves the problem (the soil should dry a bit).If no drying occurs, repot with more porous soil mix and replace drainage shards to facilitate water movement
• Cactus and succulents become “mushy”. Classic overwatering!Stop it!

Last updated July 13, 2021