Got questions about growing vegetables and fruit in Maine?

Extension experts identifies a plant sample for a client; photo by Edwin Remsberg

Ask the UMaine Extension gardening experts!

With years of experience in home horticulture and commercial agriculture, our experts help beginning gardeners achieve successful harvests, encourage gardeners and commercial farmers to donate excess produce to those in need, and use gardening as a vehicle to develop communities.

If you have a question about growing vegetables and fruit in Maine, you are welcome to

2018 Q&A

Answers are provided by Caragh Fitzgerald, Associate Extension Professor, Agriculture, UMaine Extension Kennebec County; Kate Garland, Horticultural Professional, UMaine Extension Penobscot County; Kathy Hopkins, Extension Educator, UMaine Extension Somerset County; Tori Jackson, Extension Educator: Agriculture and Natural Resources, UMaine Extension Androscoggin and Sagadahoc Counties; Cathy Kloetzli, Agriculture & Food Systems Professional, UMaine Extension Oxford County; Kathleen McNerney, Home Horticultural Coordinator, UMaine Extension Cumberland County; Marjorie Peronto, Extension Educator, UMaine Extension Hancock and Washington Counties; Elizabeth Stanley, Horticulture Community Education Assistant, UMaine Extension Knox, Lincoln, and Waldo Counties; and Frank Wertheim, Extension Educator, Agriculture/Horticulture, UMaine Extension York County.

Q: About three weeks ago I purchased a bag of six Lily Tango Blend tubers. I put them in a cool and usually dark basement. Today I got them out and they are sprouting! Same with the bag of dahlias. Isn’t it too early to plant outside? What should I do?

A: It is not too soon to plant. I would let yesterday’s rain drain from your soaking wet soil today and plant them as soon as you can, tomorrow if possible. Take care not to injure the sprouting roots if you can make room for them in the planting hole and gently cover them with soil and tamp it firm.

Here is a link to a fact sheet on planting Asiatic Lillies.

Q: Can you offer resources in names of experienced people, books, organizations, trustworthy businesses to help me figure how to landscape a new home (for me) surrounded by wetland?

A: I highly recommend checking out the following resources on our website as you begin your research. Your local Soil and Water Conservation District office is also a tremendous resource. Additionally, you are always welcome to call your local UMaine Cooperative Extension office for answers to specific questions. We are not allowed to endorse any for-profit professionals or businesses, but do recommend reaching out to neighbors to see if they have had good experiences with professionals in your area.

Q: How do I get rid of voles? They destroyed my lawn and ate my irisis and other perennial plants. I noticed all of this once the snow mounds melted in my yard.

A: We currently refer our wildlife control questions to the Maine Office of USDA Wildlife Services. Here is their link: Maine Office of USDA Wildlife Services or call 207.629.5181​ or 1.866.4US.DAWS​.

Q: As new home buyers, we are trying to build our own home garden. Would you please provide your perspective/advice on 4-5 essential tools we will need to build a thriving garden? Should we rent, purchase or borrow and what benefits these tools will provide when used properly?

A: Here are my top 5 essential tools to build a thriving garden ($ symbols represent relative cost):Top-quality watering wand and user-friendly hose set-up ($$).

  1. Watering is a very important step in cultivating healthy plants. Make it an easy chore with the right implements. I prefer a long handle watering wand to reach hanging baskets and deep into wide beds. A small shut-off valve and quick-release for swapping out hose ends can be valuable, yet inexpensive additions if you are using your hose for other jobs (washing the car, kids’ sprinkler, etc.). If your hose set up is not working for you in any way, think of ways you can improve the situation at the beginning of the season instead of struggling with it daily. For example, if you find yourself dragging your hose over the prized iris on the corner of the garden bed, place a decorative post to guide the hose around the plants. Even better, consider installing drip irrigation.
  2. Rain gauge ($). We often overestimate how much water Mother Nature provides during weather events. This age-old gardening tool will give you more confidence about making watering decisions. Most newly installed plants need about 1″ of water a week for the first season.
  3. Soil test ($). This isn’t a tool in the traditional sense, but is an important component of a gardener’s virtual tool kit. Contact your local Cooperative Extension to see where they recommend sending soil samples to gather information about soil nutrition, pH, organic matter content, and to rule out lead contamination.
  4. Tarp ($) Yes, I’m from Maine and Mainers love tarps. A simple tarp comes in handy in so many landscape situations. I use it to keep soil off my lawn when dividing perennial plants, it’s a great alternative to a wheelbarrow when I’m needing to haul a lot of lightweight debris to to the compost area, it’s very easy to clean and packable when the job is done.
  5. Bypass pruners, folding saw, loppers ($$$). If you have woody plants and a DIY spirit, these three tools will cover your bases for your residential pruning needs. Consider spending a few extra dollars on these items because they may last you a lifetime.

Q: I have read cornmeal works as a birth control for weeds in the garden and stops the weed seeds from germinating. Another article claims cornmeal mixed in your soil will bring earthworms who eat it and grow huge which in turn helps irrigates plants. Do you have any knowledge or experience with cornmeal used in this manner? We do not plant a garden anymore but we do have lots of flowers and are very interested in finding a simple solution to control weeds.

A: Corn gluten meal (CGM), when applied properly, can be somewhat effective on managing certain types of weeds before they germinate (i.e. pre-emergent control). Here’s some good information from Iowa State about timing and application rates: “Proper timing of the application is critical for good weed control. Apply it in late March to mid-April [mid-late April in Maine], at least three to five weeks before the crabgrass seeds germinate. Spread it evenly over the lawn at a rate of 20 pounds per 1,000 square feet and water it lightly into the soil. After watering, let the soil dry out somewhat so that the sprouted weed seedlings dry up and die. CGM can also be applied in mid-August to control late-season annual weeds.” It’s important to note that corn gluten meal can also negatively impact seed germination rates of crops that are directly sown in the garden so caution should be used in vegetable gardening settings or where flowers are direct-sown in ornamental beds.

Some researchers suggest that the nitrogen supplied by corn gluten meal is playing a bigger role than the germination suppression characteristics because it enhances turf growth allowing it to out compete young weed seedlings.

Sicyos angulatusQ: Last season, we discovered a vine that crept along our entire fence (covering a perennial vine), wrapped around our veg bed trellises, and crawled up a few trees. I identified it as Sicyos angulatus, or onseed bur cucumber. We’ve been here 10 years and this is the first we’ve seen of Sicyos angulatus. Towards fall, we worked to detangle it away where we could, but after learning that it is an annual plant that drops seeds, we stopped due to fear that shaking it might actually cause more opportunities for it to come back.

How do we eradicate this pesky and invasive vine? Is it best to pull off all the dried vines that are currently there? Find new ones and dig them up? I’ve been all over other forums, and read some scholarly journals but advice seems pointed towards agricrops, or asks folks to use poisonous herbicides. Our organic raised beds are very close to the fence and this Sicyos angulatus problem, so we’re hoping for non-toxic solutions, or tips on when to pull them up.

A: Thank you for the terrific photos. Having a positive ID for the weed is our first step in determining best management strategies. Yes, Sicyos angulatus is an annual weed that reproduces by seed rather than coming back from it’s root system every season. It’s good that you haven’t noticed it in prior years. This means you are probably battling a small, more manageable, seed bank in the soil. The most important non-chemical management strategy is to remove the new seedlings as early as possible via hand-pulling or hoeing. You might also want to try to collect the burs before trying to pull the old plant debris from last season. This can be a pretty frustrating job because the burs are very clingy, but it may help reduce the weed seed rain that will eventually haunt you in the future. Early seedling management is much more important that managing them after mid July because later emerging seedlings don’t typically mature to the point where they’ll produce seeds.

Q: What date should I start my flowering sweet pea seeds indoors?

A: Sweet pea seeds are usually sown directly into the garden, but if you wanted to get a jump start by growing indoors, the timing depends on your frost-free date. In central Maine, I typically use 5/30 as a pretty safe frost-free date (based on historical NOAA weather information). Sweet peas should be started 4-6 weeks before your frost-free date – here, sometime in early to mid April. Learn more by checking out our Starting Seeds at Home bulletin.

black plastic mulch and cucumber plantsQ: We are hoping to grow tomatoes, cucumbers, and a variety of hot peppers (cayenne, jalepeno, habanero) this summer and are interested in using black plastic mulch. Regarding the safety in using black plastic, is this product safe for gardening, or are there any concerns about chemicals leaching into the ground? Would cucumbers benefit from this practice, or would they prefer a cooler soil temp and be planted outside of the plastic covering? As far as adding compost to the garden, would it be beneficial to add enough to cover the entire ground beneath the plastic, or only in spots where plants will be placed through the plastic?

A: Plastic mulches have been used in farm and garden situations since the 1960s. I am not aware of any studies indicating any danger of leachates from the plastics causing health problems. The issue often cited is the disposable waste problem and the difficulty with recycling plastic mulches.

It is well established that using black plastic mulches can boost warm season crops such as peppers and cucumbers to get both earlier and higher yields. They help warm the soil, keep down weeds and hold the moisture in the soil. Many farmers and gardeners run drip irrigation lines underneath the mulch to be able to water under the plastic when and if the soil does dry out.

If you have enough compost, cover the entire bed with a half an inch and lightly rake it into the top of the soil (do not deeply incorporate it). If you are limited with the amount of compost you have put a couple of trowels in with your transplants and mix it with the native soil around the transplant hole.

Here are some fact sheets on using plastic mulches in the home garden:

Here is one on using a variety of mulches including organic mulch:

mulched pathways in garden at Brae Maple FarmQ: I read that beets should be mulched with 2-3″. I’ve never done that and wonder if it’s a good idea?

A: I am not sure where you read that, however, I would think that 2-3 inches of an organic mulch here in Maine with our sometimes cool wet springs could keep the soil too wet and cool which could cause disease problems. I would recommend a light covering of mulch up to 1 inch be applied once the beets are established. Grass clippings make an nice light mulch, but be sure you do not get them from a lawn that had any weed and feed type products or any herbicide treatment.

Q: I have three acres of land in Vassalboro, and would like to rent it to a fellow who wants to grow corn for his cattle. I am interested in an estimate on how much that land is worth by assuming it had been used to grow corn before and is ready, any advice? I have no clue. Even a ballpark figure (per month) would be great!

A: A traditional starting point for negotiating leasing your land to be farmed by someone else is the value of the annual tax rate for the acreage in question. In that regard you are at least recouping your annual tax rate on that acreage. You should always have such an agreement in writing with the terms clearly spelled out. You may want to require that the lessee make improvements on the land while farming such as soil testing, lime applications and management of soil organic matter. The Beginner Farmer Resource Network of Maine has a section dedicated finding and accessing land that I think you will find very helpful. Scroll down to the section on Resources Related to Tenure Agreements.

Here is a Tutorial on Understanding and Negotiating Leases for New England Farms (PDF) which I think you will also find very helpful.

Q: What would be the correct row formation e.g., how many inches/feet apart to seed for growing beets in our Jefferson mid coast region?

A: Sow beets 1 inch apart in the row​. Each beet seed is actually a cluster of 4-5 seeds. The reason for the close spacing is beets are tough to germinate well in the garden without skips in the row. When they germinate the seed clusters that emerge successfully will have 3-4 seedlings tight together. Thin them to an ultimate spacing of 3-4 inches in the row to allow each plant enough sun, space, water and nutrients. Check the seed packet for their final thinning recommendations as some varieties are larger than others.

Here is a link to a fact sheet on Growing Beets in the Home Garden.

daffodilsQ: Our septic system is surrounded by five large boulders so people would not drive over it. We would like to plant flowers on our Septic Tank & leach field. Which types of flowers? Can I do hydrangeas in this area? We live in Lewiston, which is Zone 4 – 5.

A: It might be best to avoid planting hydrangeas all together. Even herbaceous perennial varieties of hydrangeas can have fairly extensive and deep root systems that could cause problems with a septic field.

I would recommend you go with lawn grasses, annual flowers (as they die back each year) and herbaceous perennial flowers which are not deeply rooted such as asters, echinacea (coneflowers) or rudbeckia. Shallow rooted bulbs such as daffodils and crocuses would also be fine over a septic field. Avoid edible plants such as vegetables and herbs and please see this fact sheet: Vegetable Gardens and Septic Fields Don’t Mix.

strawberriesQ: Each spring I have near complete loss of my strawberry and raspberry crop due to yankee clipper weevils. There is a perennial bed near by which I think is where they come from. Any suggestions?

A: Strawberry Bud Weevil (SBW) or Strawberry Clipper Weevil have been known to reduce fruit set in a planting by up to 75%. Although this amount of loss is significant, strawberries can compensate somewhat by producing larger size of the remaining fruit. The SBW lays its eggs on the buds of immature fruit, which in Maine usually occurs in late May to early June. SBW damage to plants will often go unnoticed by the gardener as it occurs before the fruits ripen.

After laying an egg in the immature bud the SBW will chew through the pedicle attached to the bud. The clipped bud then drops to the ground and the larvae emerges from the egg and feeds within the clipped bud for about three weeks, after which the larvae pupate either within the bud or in the soil below it. The adults then emerge from the pupae and find overwintering sites in the edges of fields in weedy sites. They emerge following spring and repeat the cycle. Cultural control options therefore include management of weedy areas at the edges of fields as well as good sanitation and bed renovation as described in this Growing Strawberries Fact Sheet.

Pesticides should only be used as a last resort and timing for an application would have to done during bud development of the strawberries in the spring before you start to see damage and before the adults emerge and lay their eggs. Once the eggs are laid both the egg and emerging larvae would be protected from any sprays within the bud. When using pesticides follow the directions on the label carefully and make sure that the pest (SBW) is listed on the label.

Q: My lilacs all seem to be succumbing to root rot. Last year I put some fungicide in the soil. A week or two later, Ililac with stressed flowers and leaves saw two dead shrews and a dead chipmunk in the yard, which might have been coincidence. Is it likely the lilacs can be saved? If not, is there something that is pretty, flowering, hopefully native, not too tall that can be planted where they were? One lilac that completely died was next to a rhodo, which seems to be fine.

A: Lilacs are very durable, so we usually look for environmental problems first. If you think you have a diseased plant, we have free pest and disease testing available. UMaine Cooperative Extension Insect and Plant Disease Diagnostic Lab.

Drainage: Lilacs like full sun and rich, well-drained soil. Has the drainage changed around the house? Is there a new downspout near the root zone? Runoff from a new driveway or addition? If so, the roots may not be able to get enough air to function well.

Stress: For the last two seasons, we’ve had very wet springs and very dry summers/falls. This can also stress plants, even ones that are old and well-established. Fertilizers can also cause root stress because they are salts and draw water away from the roots.

Soil pH: Lilacs also like a higher pH (6.5 – 7.0) than Maine soils usually offer. If the rhododendron is near by and doing well (4.5 – 6.0), the pH may be low. I would do a soil test, see what the pH is, and go from there with lime or sulfur, depending on the test results. It will also show what nutrients are in your soil.

Pruning: If the lilac has dead or broken trunks or spindly suckers, it may be good to prune it soon and select some of well-spaced and stronger growth to remain. Pruning is good for most multi-stemmed shrubs.

Here’s a video on how to do this: How to prune a lilac bush.

Other plants: If the lilac isn’t doing well by July, yes, it might be time to consider a different shrub in that location. We have a lot of resources on plants for different locations: Plants for the Maine Landscape.

For more information on gardening, feel free to bookmark this part of our website: UMaine Extension Garden & Yard.

apples on treeQ: Last year we began beekeeping and so far they have survived this tough winter. Last year was also the first year our apple tree produced fruit. However, it was infested by worms. Is there a product I can use on the tree that won’t harm the bees? I would rather have the bees healthy.

A: There are a number of insect pests that may be called worms in apples. For specific timing and control options, we’ll need to know which it is, since those options vary by pest. Can you send us more information about the worms? If not, you’ll need to get a sample to the UMaine Extension Insect and Plant Disease Diagnostic Lab when you see the problem again. Here is information about sending samples. If you’re looking for good, general information about backyard apple production, take a look at UMaine Extension’s Growing Fruit Trees in Maine.

Q: I forgot to store my leftover 2017 seeds in my basement. They have been in my garage since October until now. I am wondering if they can be used for this upcoming season? They were in a lidded plastic container.

a variety of seeds
© Lisa Looke, Photos courtesy of Wild Seed Project

A: Your seeds should be fine.  Although storing seeds at a constant cool temperature is ideal, they should have survived in your garage for the winter.  Some seeds, like onions have a very short shelf life, only a year or two. But other seeds could still be viable for up to several years.  There is a chart about seed longevity at the bottom of this factsheet, An Introduction to Seed Saving for the Home Gardener that will tell you the average storage life under ideal conditions.  You can test the germination rate of your seeds by choosing ten seeds and placing them between damp paper towels.  Check your seed packet to see the expected days until germination and then check your seeds to see how many have sprouted.  The number of sprouted seeds will tell you your expected germination rate of the seed stored in your garage.  If it is low, you can either plant the seeds thicker than recommended and then thin, if necessary, or just buy new seeds.

Q: I am moving to a small island for the summer. Do you have recommendations as to what vegetables will grow best when surrounded by the sea and all the stressors this implies?

A: Gardening on an island can be as successful as gardening in other locations.  If you are going to be a summer resident, then you may want to focus on short season crops rather than planning on season extension.  If you are in the shade, planting greens, which require less sun, will ensure greater success.  If you have sun, then check out  Vegetable Varieties for Maine Gardens to find the shortest season varieties that should do well in your location.

Q: What gardening zone is Searsport?

A: Searsport is most likely a Zone 5a or 5b depending on how close to the coast you are. Please see fact sheet, Plant Hardiness Zone Map of Maine.

The map and your own observations about exposure, wind strength, etc. may help you determine which zone is appropriate for your landscape.

Q: I noticed that the euonymous alatus (burningbush) is listed as a non native invasive species. Does this include euonymous compacta? I love these bushes but I don’t want to perpetuate harmful species.

A: I believe you are referring to Euonymus alatus ‘Compactus’. Yes, this is a non native invasive species in Maine. Legislation that took effect on January 1, 2018 prohibits the sale of these plants in Maine. This does not mean that you cannot continue to grow them on your property. However, they do have an impact on the surrounding ecosystem. I have seen large stands of it take over the forest understory in Massachusetts and in Boothbay, Maine.

Quoting the Invasive Plant Atlas of the United States, “Euonymus alatus can invade not only a variety of disturbed habitats including forest edges, old fields, and roadsides but also in undisturbed forests. Birds and other wildlife eat and disperse the fruit. Once established, it can form dense thickets, displacing native vegetation. It is native to northeastern Asia and was first introduced into North America in the 1860s for ornamental purposes.”

Spotted Wing Drosophila Larvae in a rasberry
Spotted Wing Drosophila larvae in a raspberry. Photo by David Handley.

Q: I had small worms in my blueberry and raspberry fruit last year. I vaguely remember reading about a new fly pest. Can you give me some ways to prevent the recurrence? Do they also attack strawberries? The fruits softened as they ripened.

A: It sounds like you might have spotted wing drosophila. You can find out more information about them and how to make monitoring traps on this University of Maine Cooperative Extension web page Fact sheet — Insects (scroll down to the bottom). You can also read and sign up for the spotted wing drosophila blog that is available for free on the UMaine Extension Highmoor Farm website. It is a great resource for information and seeing the movement of the pest around the state next summer. If you are planting any new fruit crops, choose the earliest maturing variety you can choose for your area.

Q: Our birch tree is severely bent due to ice buildup and it doesn’t look like temperatures will warm up anytime soon. I am thinking of pruning it back because it is almost on a power line and is covering our walk. Is there anything I can put on the wounds to help it heal and not bleed out sap when it thaws?

birch tree bent under the weight of snow and ice
Photo by C. Eves-Thomas.

A: Don’t ever touch or work on a tree that’s near a power line. Any work that needs to be done near power lines or houses (or any complex work in general) should be done by a licensed Maine arborist. They’re trained to know the physiology of trees and also how to work safely. To find an arborist near you, see this list of arborists by town. Be sure to read “How to hire an arborist” fact sheet (PDF).

Once the ice is off of the tree, it may become upright again, though birches can remain bent permanently.

Regarding your question about applying tar on wounds: it is no longer recommended. Certain trees like sugar maples and birch should not be pruned in late winter or spring because of their sap flow. (Late summer into fall is best for these species, but most others are best pruned in late winter when dormant.)

Here’s more info about care and pruning of trees and shrubs:

Questions & Answers from 2017

Questions & Answers from 2016

Questions & Answers from 2015

Questions & Answers from Previous Seasons