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Q&A: Potato fruit??

Q: We found little green globes on the top our our Mega Chip potato plant.  We have 29 hills and only a few have these on them. They are about 3/4 inch in diameter and always in clusters. I haven't dug underneath the plant to look for potatoes yet so I don't know if the plant is producing potatoes or not. I've raised potatoes before but have never seen anything like this.

A: They are the fruits of the potato plant. Some people call them "potato berries" or potato fruits. They look like tomatoes, but are NOT edible. Potatoes and tomatoes are both from the nightshade family. The potatoes produced from these seeds will not have the same characteristics than the plants they came from hence the reason farmers start with tubers and not seed. According to Iowa State University IPM News, "The potato fruit are of no value to the gardener. Potato fruit, as well as the plant itself, contain relatively large amounts of solanine. Solanine is a poisonous alkaloid. The small fruit should NOT be eaten. Since potatoes don't come true from seed, no effort should be made to save the seed."

Here are some university resources with additional information:

Q: I have a garden in northern Minnesota. Several years ago I installed a retaining wall on part of my vegetable garden. We have very sandy soil and the bed is in full sun.  Plants do not grow very well close to the wall yet they grow well just a couple of feet away. Could there be a problem with leaching from the landscape block?

A: The cement used in manufacturing the wall block may cause some issues around soil pH, but usually only in the immediate few inches around the block area, and unless you are trying to grow blueberries or other plants that require low pH soils, it won't be significant. Likewise, the blocks may hold a little solar heat if they are dark colored, but it too isn't significant. Light colored cement is more likely to reflect light / solar heat and stay fairly cool.

It is more likely the quality of the soil along the wall. When block walls are built, drain tile may be used to move water away from the wall to reduce pressure on the block. Clear stone is laid in a strip about 8-10" into the bed and over the drain tile against wall block to promote good drainage through soil into the tile. I believe these conditions combined with your sandy soil, which dries out quickly and lacks organic matter for plant growth, is what is causing the problem with your plants along the wall. Essentially they are trying to grow in dry, rocky soil.

While you don't want to compromise the performance of your wall by digging into or removing the materials that are providing adequate drainage, you approach this several ways:

  • Avoid root vegetables or plants with tap roots in this area because of the rock, shallow soil.

  • You could amend the soil over the clear stone with compost to increase water holding capacity for plant roots and then choose perennial edibles like strawberries as a border along the block wall. Be careful not to mix the compost into the clear stone and doRed Cabbages.JPGn't mix stone into the top layer of soil / compost. Alpine strawberries are great border plants because they form tidy, mounds (vs. runners) suitable to a border. Perennial plants would be a good choice for the area along the block because you would not need to replant / re-dig and could just top dress the soil with compost each year around the plants, slowly improving that soil area.

  • Red cabbages also make really neat borders along wall block as their large leaves grow over the block a bit and can tolerate some drier conditions.

  • Instead of edibles, plant ornamental perennial plants that have shallow root systems and do well in drier conditions like sedums to add some color and interest to the garden.

Rheum rhabarbarm Canada Red.JPGI have never had so many questions about rhubarb in the 15 years I have been a Master Gardener or the 6 years I have been state director. Many people have contacted me or Master Gardeners about whether it is safe to east rhubarb that has been subjected to frost damage.

The University of Minnesota does not have a specific publication about this, so I went to other universities (see below). Here's what I learned:

If rhubarb has suffered apparent frost damage, it is recommended you not eat it as oxalic acid from the leaves may be transferred to the leaf petioles (the stems we eat) and is considered toxic. This is particularly true if the stem has been damaged by freezing temperatures and / or is mushy. When in doubt, throw it out.

When you pick rhubarb (not frost damaged), cut the leaves off the stems immediately and compost them (Yes, you can compost them because the oxalic acid and soluable oxalates are not readily absorbed by the roots of plants. Compost containing decomposed rhubarb leaves can be safely worked into the soil of vegetable gardens. Source: Jauron, Richard, Iowa State University Horticulture & Home Pest News, May 2, 1997 issue, p. 57).

You can then use the rhubarb as usual or chop and freeze it. Freezing the stems only does not produce a toxic effect as it is the leaves, not the stems, that contain oxalic acid.

Here are some good resources about rhubarb and toxicity:

General information about growing rhubarb:

A: Sometimes Master Gardeners get questions from citizens asking if they can hire a Horticulture student or a Master Gardener to help them with landscaping around their home.

Hiring a Horticulture student to do landscaping: The Department of Horticulture Science P1040674.JPGno longer has landscape design classes in its curriculum. Landscape design classes merged with Landscape Architecture in 2009. People or businesses wanting to hire a University of Minnesota student should post a job description and salary on is the U of M's online database to help connect students and alumni with employers, volunteer organizations, and internships across the country.

Hiring a Professional Landscaper:
Master Gardener volunteers don't provide free labor for such projects. The caller should consider hiring a landscape professional. They might want to contact a local garden center that offers professional landscaping or call the MN Nursery and Landscape Association. Or, if there's a great looking landscape in the neighborhood,  the caller could simply ask the homeowner who did the work. There are also lots of opportunities to meet and talk with landscape professionals at home and garden shows around the state.

 A: No. The University of Minnesota does not provide compost, farmpost, mulch, soil or plants to any entity or individual outside the University. Our LandCare Facilities Management follows best sustainable landscape management practices by reusing landscape waste as compost, soil amendments, wood mulch, etc. Unfortunately, LandCare produces only enough of a supply of these for use on the various University campuses they manage.

However, here are some sources for landscape materials in Minnesota:

MN State Hort Society / MN Green Program
Seeds and plants (must be a member of MN Green)
Contact: Vicky Vogels
(651) 643-3601 ext. 211
(800) 676-6747 ext. 211

Gardening Matters
Resources for community gardens
Sabathani Community Center
310 E. 38th St., #204, Minneapolis, MN 55409

The Mulch Store
Compost, mulches; some sites accept home yard waste including ash
Main info: (952) 946-6999
Monday through Friday from 8:00 AM until 4:00 PM with a limited staff.
Saturday hours will begin April 7th.

Four locations:
14800 Johnson Memorial Dr. (Hwy. 169)
Shakopee, MN 55379
(952) 445-2139

1030 W. Cliff Rd.
Burnsville, MN 55337
(952) 736-1915

Empire Township
16454 Blaine Ave. E
Rosemount, MN 55068
(651) 423-4401

4275 Creek View Circle
Minnetrista, MN 55331
(952) 446-1056

Communities sometimes also have free mulch / compost for residents. Please check with your local municipality.

MN Landscape Arboretum Summer House / Apple House
Landscape plants, landscape ornaments, pots; local in-season fruits and vegetables including MN apples
Open during the growing season May - October, 10am - 6 pm daily
Main Arboretum information: (952) 443-1400

By Bob Mugaas, Extension Educator. Posted by Julie Weisenhorn

The best thing people can be doing right now is get some moisture to their lawns to reduce the stress from the very dry conditions of late August through most of September.  Two or three good soakings either from rain or irrigation before freeze up will help restore internal plant moisture levels although you're not likely to see a lot of vigorous new growth yet this fall due to falling temperatures and the significantly shorter daylengths. 

Too late to be fertilizing. Remember also that with the very dry and slow growth conditions over the last month and a half, the plants haven't been using much N either. At this point, I would wait until spring to apply some additional N. Timing for that spring application should be around the middle to end April perhaps even into early May depending on where you are in the state.  Rates should be about 1/2 pound of N per 1000 square feet as you do not what to encourage too much growth too quickly at that time of year.  This will be more of a supplemental application to ensure ample soil N levels for healthy growth.
Depending on how you look at it, it is either too late or too early for seeding.  In the first case, right now would not be a good time for seeding as the very small young seedlings often have a difficult time surviving winter stresses.  In the latter case, which is referring to a process we term dormant seeding, it is too early for that since soils are still warm enough for germination to occur.  The purpose of dormant seeding is to get the seed in the ground just before it freezes.  Those cold soil conditions will inhibit germination this fall but the seed is in position to germinate and begin to grow earlier next spring.  Dormant seeding in the Twin Cities area doesn't usually begin until early November or in some years the very latter part of October.  This timing can be adjusted up or down slightly depending on where you are in the state.

A good resource for the recently updated section on SULIS Turf Maintenance
Malus keepsake fruit1 254.jpgBy Emily Hoover, posted by J. Weisenhorn

Question: What is the implication of the freeze warning on the apple crop?

Answer: It depends on how cold it gets. The temperature within an orchard is not consistent. The "rule of thumb" is about 10% of the fruit on the tree will freeze if the temperature drops to 28 degrees Fahrenheit and remains so a few hours.  Ninety percent of the apples will freeze if the temperature drops to 25 degrees Fahrenheit and remains so for a few hours. 

However, the level of sugar in an apple also changes the severity of the event. The higher the amount of sugar, the lower the temperature has to be before freezing will occur because sugar lowers the freezing point of a solution. (Think Chemistry 101). Note that if the fruit freezes on the tree, but is not touched until it thaws, the fruit is fine to harvest.

Emily Hoover is a professor and department head in the UMN Department of Horticultural Science. Her research focuses on apple rootstocks.

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