Failed Raised Garden Bed

Asked June 26, 2013, 9:20 PM EDT

I live in so. Ore., planted a 4 x 5 raised bed with good planting mix from Hilton Fuel, put in veggies, (tomatoes, cukes, squash and bell peppers). At first watered twice a day as it was 90 degree plus weather, then went to once a day, the tomatoes began to look wilty, (no did not water from above but usually watered in evenings). It is as if the garden just never took off good and grew. There is yellowed on cukes and squash, and tomatoes, yellowed, with some leaf curling. Bell peppers leaves look curled some too. They all have tiny black spots underneath leaves. I am suspecting bacterial spot, as I do not see spider mites or aphids. Frustrating as waited for a couple of years just to be able to have a bed built, and afford a little dirt. Waaaah. Not sure if they can be saved. To prepare raised bed, we put newspapers and cardboard as ground here is rock hard, then piled on soil. I believe soil was half potting soil, half compost, reputable company. Wondering if it came in on some plants.

Jackson County Oregon

3 Responses

Sometimes when we do things we think will solve a problem, it just creates more problems. We strongly suspect that your rock hard soil underneath that cardboard and newspaper has created somewhat of a "perched lake". The good drainage properties of your raised bed soil let all that watering drop right down to the impervious layer and pool there. Drowned roots beget yellowed leaves on most any plant. The roots cannot access nutrients for the leaves to carry on making chlorophyll because they are surfeited with water. Next time, loosen the rock hard stuff with a spading fork before covering it up with newspaper. Add to that, personal experience with the mix you are using tells me that decomposition of the organics may still be going on-- this results in Nitrogen,the green growth element, being used up by the organics in the soil mix and leaving not enough for the plant, creating yellowing plants.. Add some fast acting nitrogen rich fertilizer to combat what is called nitrogen deficiency. (Preferably you would have added Nitrogen before planting and let the soil work it in for a couple of weeks or more.) The result of Nitrogen deficiency is yellow leaves. A third consideration for your problem is the weather, about which we can do very little. Yes, it was hot about planting time. Water was not the only answer--shade cloth over newly planted starts would help control the temperature on the ground. Then it turned unseasonably cool-- not enough warmth or sun for those warm season vegetables. Finally, about the possibility of bacterial spot. This is not a super common disease in the west and it is unlikely to have developed on small plants so rapidly. A far more likely culprit (if there is an insect problem) is aphid. They do come in black colors. It is hard to distinguish aphids sometimes, but curled, yellowing leaves are highly suspicious. Without seeing the underside of the leaf in the photo, it is difficult to diagnose exactly what is causing black spots. Fungal spots usually start out browning or yellowish, then that part of the leaf dies and drops out, leaving a hole. Ditto with bacterial spots, which may range in color from purplish to blackish. To obtain an accurate diagnosis of insect problems, should you still suspect any, visit the plant clinic of OSU Jackson County Extension, 569 Hanley Road, Central Point. Telephone 541-776-7371. There are also some excellent references on the web for growing vegetables in raised beds. Check out extension.oregonstate.edu/publications and search on raised beds. Good luck with the next try!

Wow, thanks for the info. I do not see aphids though. I forgot to mention the raised bed is only 8 inches high, so I would imagine that would add to the trauma if not getting good drainage. The plants are trying to survive. Any suggestions, or just give up? I did try fertilizing with some liquid kelp fertilizer and sprayed with a natural aphid spray. I wonder if this is futile.

It never occurred to me to include the underside of the leaf, so I went out and took a picture and included it.


Thanks for the second photo--unfortunately it doesn't show clearly enough to see any black spots , drop throughs from dead leaf spots, or any sign of frass ( bug poop). We don't think, given that all of your plants seem to be suffering the same problem, that it is due to something"brought in" on the plants. There could be some soil contaminants, but this is highly unlikely.There still could be the possibility of mildew or other surface damage (sunburn, white spotting from failure to acclimatize (harden off) your transplants before planting, other causes). We don't think you should "give up" except on plants that are very defoliated or wilted and have no new growth. Kelp extracts are good sources of micro-nutrients. They are not generally high in Nitrogen, which is what we believe your plants need a good dose of. If you want to stlay organic, look for a chicken-poop based fertilizer. Check the first number of the per cents of nutrients (i.e., 5-10-10).That is the per cent of Nitrogen and we would recommend at leastl 8 in this case. One other thing you could try, if you have space between your plants, is to take a sharp probe (metal, shapened bamboo pole, other implement long enough to penetrate through that layer of cardboard into the ground, and poke a bunch of holes to limprove the drainage.You can also drill side holes at the very bottom to help the drainage. After all, the Medford Gospel Garden is a series of boxes built on the old asphalt parking lot. Drainage there is via raising the box slightly off the ground and drilling holes, just as you would in a pot. Most gardens do not need water more than once a day, and even that should be carefully controlled. You want to strive for evenly moist, not flooded! Water in the early morning so plants dry off during the day--that way mildew can be controlled. Keep at it!