Cosmos are very easy to start outside and do not need to be started inside, however, you can start them inside 6-8 weeks before the last frost.
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Learn to Grow
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- Garden Guides
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Planting Guide
- How do I plant mini tuber potatoes?
- What should I do when my bare roots arrive?
- How do I plant my garlic?
- What should I do when my potted annuals arrive?
- What should I do when my fruit tree arrives?
- How and when should I divide my herbaceous perennials?
- What should I do when my berry plants arrive?
- How deep should I plant my fall bulbs?
- Do you have any tips for planting fall bulbs?
- What should I do when my fall brassicas arrive?
- What should I do when my potted perennial arrives?
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Reference Charts
- Do you have a quick reference for blueberries?
- Do you have a fruit plant quick reference chart?
- Do you have a quick reference for peas?
- Do you have a quick reference for onions?
- Do you have a quick reference for cucumbers?
- Seed Counts
- Do you have a quick reference for sunflowers?
- Do you have a quick reference chart for herbs?
- Do you have a quick reference for fig trees?
- Do you have a scoville chart for hot peppers?
- Do you have a quick reference for squash?
- Do you have a quick reference for zinnias?
- Do you have a quick reference for pumpkins?
- Do you have a quick reference for marigolds?
- Do you have a quick reference for beans?
- Do you have a quick reference chart for spring garlic?
- Do you have a quick reference for corn?
- What seeds do you sell as seed tape?
- Do you have a quick reference for raspberries?
- Do you have a quick reference for strawberries?
- Do you have a quick reference for blackberries?
- Do you have a tomato resistance chart?
- Do you have a quick reference for roses?
- Do you have a quick reference for hydrangeas?
- Do you have a quick reference for fall garlic?
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Getting Started in Gardening
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Gardening 101
- How can I support my tomato plants as they grow?
- How much water do tomatoes need?
- How much sunlight do tomato plants need?
- Ho do I use the self-watering seed starting tray?
- How do you plant garlic?
- When does Days to Maturity (Days to Harvest) Start?
- Do you treat your seeds with Neonicotinoid pesticides?
- What are some tips for beginning my garden?
- How do I direct sow seeds?
- Can I use last years seeds?
- What are the types of Zinnia?
- How long does it take for marigolds to bloom from seed?
- Will my annuals come back next year?
- What are the types of strawberries?
- How do you tell if raspberries are ready to pick?
- What are the types of raspberries?
- What are the types of peppers?
- What are the classes of tomatoes?
- What are the types of cucumbers?
- What are the types of sweet corn?
- What are the kinds of beans?
- How do I plant asparagus?
- What are some quick tips about vegetable gardening?
- What are warm season vegetables?
- What is the meaning of workable soil?
- What are cool season vegetables?
- Can I use an overhead sprinkler to water my garden?
- What is seed tape?
- Which vegetables are perennial?
- What is a complete fertilizer mean?
- What does germination mean?
- What is a bedding plant?
- What is a cotyledon?
- What does Biennial Mean?
- What vegetables can you use Burpee Booster on?
- How do I use the Burpee Booster?
- What does Everbearing mean for strawberries?
- What does June bearing mean for strawberries?
- What is a Chill Hour in fruit plants?
- What kind of flowers only last one year?
- What kind of flowers come back every year?
- What does full sun, part sun and full shade mean?
- How do you plant Seed Tape?
- What are some easy Vegetables I can grow in my area?
- What are some easy flowers I can grow in my area?
- How should I store my seeds?
- How do I harden off my plants?
- Do you have any gardening videos?
- Do you have extra plant-o-gram sheets?
- What is the difference between Organic and Non-Organic seeds?
- What are some tips for kids to garden?
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Recommendations
- What are the best beets for juicing?
- What are your best heat tolerant tomatoes?
- Do you have any Persian type cucumbers?
- What are spinach substitutes I can grow in the summer?
- What are the best carrots for storage?
- What are your most drought tolerant blueberries?
- What are the best carrots for clay soil?
- What are the best carrots for containers?
- What are the best baby carrots?
- What are some of the horticulturalists' favorite vegetables?
- What impatiens are resistant to Downy Mildew?
- Do you have a squash that is vine borer resistant?
- What are some easy to grow flowers for full sun?
- What are some easy to grow flowers for shade?
- What are some flower options for wet areas?
- What are some flower options for dry areas?
- What are the best flowers to attract hummingbirds and bees?
- What are some deer resistant flowers?
- What are some container friendly flowers?
- What are some vine plants?
- What are some northern perennial flowers?
- What are some southern perennial flower options?
- What are your best all around tomatoes?
- What are your best wilt resistant tomatoes?
- What are your best blight resistant tomatoes?
- What are your best nematode resistant tomatoes?
- What are your best low acid tomatoes?
- What are your best high acid tomatoes?
- What are your best container tomatoes?
- What are your best juicing tomatoes?
- What are your best tasting tomatoes?
- What are your best canning tomatoes?
- What are your best tomatoes for sauce making?
- What are your best Campari substitutes?
- What vegetables grow quickly?
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Seed Starting
- What tips do you have for seed starting?
- How do I thin my plants in a seed starting set?
- How many plants should be in each cell of a seed starting set?
- What are are the dimensions of Superseed Seed Starting tray 8 XL cell?
- What are the dimensions of the SuperSeed Seed Starting Tray 36 cell (96515)
- How much water should be in the bottom tray of the seed starting tray?
- Do you have any tips for expanding the Super Growing Pellets?
- How do I get my seeling ready to be planted outside?
- When should I remove the heatmat?
- When should I remove the lid (dome) on my seed starting kit?
- Do I shell the peanuts before planting?
- Do I remove the netting off the coir pellets when I plant them in the garden?
- What does direct sow (garden sown) mean?
- How long do I leave my grow light on?
- What are the dimensions of the SuperSeed Seed Starting Tray, 16 XL Cell (93412)?
- What are the dimensions of the XL ultimate Growing System (96089)?
- Which side of the self watering mat goes up in the Ultimate Growing System?
- What are the dimensions of the 72-cell Ultimate Growing System (96004)?
- Is your coir buffered?
- Do I need to wash the coir before using?
- What is the best fertilizer for seedlings?
- Why didn't my seeds germinate?
- If I cannot use all of my seed, how to I store them?
- Why did my seedling just bend over and die?
- What do I do about white mold on my soil?
- Why are my seedlings leggy (spindly)?
- Can I leave my grow light on for 24 hours?
- When should I remove the heat mat?
- Why does the lid on my grow kit not fit tightly?
- Which color side of the self-watering mat should be up?
- What is the pH of your coir?
- What is the coir made from?
- Why aren't my coir pellets expanding?
- What seed starting accessories do you recommend?
- Seed Starting Indoor/outdoor Guide
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Gardening 101
-
Gardening FAQs
-
Garden Question Library
- Why is my 'Big Mama' tomato leaves curled?
- Are the tires of the Ultimate Gardener Cart (99103) pneumatic?
- Where is Sea Magic manufactured?
- What is Sea Magic (99004) made from?
- Do you have the directions for Sea Magic 99004?
- Do you have any self-pollinating cucumbers?
- What are some plants that tolerate rocky soil?
- Will the 12 in 1 garden bed get too hot in the summer or in hot climates?
- What are the assembly instructions for the 17" Tall 42" Round galvanized garden bed?
- What comes with the Worm Factory 360?
- What are the dimensions of the Adjustable Frost Protection Kit (99968)?
- When do I havest beans?
- What kind of support do beans need?
- When is the best time to plant beans?
- Can I get more information on the Crimson Star Goji Berry (22311)?
- Do you have the instruction for how to use the Burpee Enhanced All Purpose 5-5-5 plant food?
- Do you have the instructions on how to use Burpee Enhanced Tomato + Edibles 8-4-4?
- My kohlrabi did not form a bulb can I still eat the plant?
- Why does the kohlrabi bulb taste hot?
- Why is the kohlrabi bulb cracking?
- Why is my kohlrabi bulb woody?
- Do you have instructions on the Deluxe LED Glow-N-Grow Light Kit?
- Do you carry Cucamelon seeds?
- How long does it take to see the potato plants grow?
- What is the difference between male and female cucumber flowers?
- What were some common Kitchen Garden Vegetables from the early 1900's?
- Do I need two varieties of figs to get fruit?
- Why are my carrots pale yellow?
- How deep does a pot need to be to grow carrots?
- Why do my stored carrots taste bitter?
- What is the the average first and last frost date for my growing zone?
- Do you have directions of the Burpee clock?
- Do you have spinach that does not have oxalate crystals?
- What are the Dimensions of the Round Garden Bed?
- Do you have the instructions for attaching the Tomato Cage Extender to a Tomato Cage?
- What are the dimensions of the Mr. Spin Compost Tumbler?
- What are the dimensions of the Ms Tumbles Compost Tumbler?
- When should I start my Amaryllis?
- What is the care for Wintergreen plants?
- What is the care for the Lawson Cypress?
- What is the care for the Lemon Cypress?
- What should I never compost?
- How do I keep the greenhouse clean?
- What type of flooring do you recommend for your greenhouses?
- What is the snow load capacity of the Riga Greenhouse?
- How does the Automatic Window Opener work in your greenhouses – does it need electricity?
- What kind of ventilation is provided in the Riga Greenhouse?
- How long does it take to assemble the Riga greenhouse?
- What is the after care for Amaryllis?
- What are the assembly instructions for the 12 in 1 raised bed?
- How to grow Amaryllis.
- What comes with the 12 in 1 Garden Bed kit?
- What are the dimensions of the new 12-in-1 raised bed?
- Why are there two different seeds in the seedless watermelon packet?
- Do you have instructions for the Pro Series Cages?
- How do I store Canna bulbs for the winter?
- How do I store Caladium bulbs?
- How do I store tuberous Begonias bulbs for the winter?
- Do you carry Lisianthus seeds?
- What are the names of the onions in the set collection?
- Is the tomato and annual or perennial?
- How to store an elephant ear bulb for the winter.
- How to store Dahlia bulbs for the winter.
- How to store Gladiolus corms for the winter.
- Can I overwinter my elephant ear inside as a housplant?
- If I am expecting a frost, what should I do?
- Why are my tomatillos sour or bitter?
- Do the seeds of Nasturtium need special care before planting?
- What does Genetically Modified Organism (GMO) mean?
- Can I plant strawberries where I planted tomatoes last year?
- What are the ingredients in the Burpee Booster?
- What is a "sour" soil?
- What is a "sweet" soil?
- Why did my lisianthus arrive with the flowers cut off?
- What are inoculants for beans?
- When do I cut back the asparagus ferns for the winter?
- How old are your asparagus roots (crowns)?
- Why are my garlic bulbs for planting so small?
- Can I plant my garlic if it's sprouting when it arrives?
- Why did my kohlrabi not form a bulb?
- Will Echinacea bloom the first year from seed?
- What does thinning mean?
- Which flowers are edible?
- How do you prechill Columbine?
- Why is my white cauliflower turning green, yellow or off color?
- How do I harvest pumpkins?
- How do I sanitize a container?
- How many seeds per cell should I plant?
- How do I plant seedless watermelon?
- What vegetables are safe for dogs to eat?
- What plants are toxic to my pet?
- Why does my fig tree have 2 different kinds of leaves?
- What should I compost?
- What are the benefits of adding organic matter to my soil?
- What are these white spots on my tomato leaves after transplanting?
- How much can I expect from my tomato plant?
- What are suckers and how do I remove them?
- Can I grow tomatoes in a container?
- How should I store my sweet potatoes?
- I can't plant my sweet potatoes right away. Can I hold them?
- My sweet potatoes arrived wilted. Are they dead?
- How can I reduce pungency when using raw onions?
- How do I store whole peeled onions?
- What is the best way to store onions?
- How many cups of chopped onion will a medium onion yield?
- How do I reduce tearing when cutting an onion?
- Do you have the soil tester instructions?
- Do you have a MSDS for vermiculite?
- Do you have a MSDS for Bonemeal?
- Do you have an MSDS for the potting soil?
- Do you have an MSDS for Bloodmeal?
- What should my soil pH be for my vegetables or herbs?
- What should my soil pH be for my flowers?
- When do I harvest eggplant?
- Why do my bean plants have flowers but no pods?
- Why do I have no flowers on my bean plants?
- Are your bean seeds treated with inoculants or fungicides?
- Can I move my asparagus after planting?
- How many plants do I need for a family?
- How can I get that white asparagus I see in stores?
- Are the red asparagus berries edible?
- Do I need male and female plants to get asparagus?
- What does the season mean for blueberries?
- Can I grow container varieties of blueberries in the ground?
- Are there seedless blueberries?
- Do I need to do something special to grow blueberries?
- When will I get fruit from my blueberry plant?
- Can I grow hydrangeas in containers?
- Why are my hydrangea flowers turning green?
- Why isn’t my hydrangea blooming?
- How do I change the flower color of my hydrangea?
- Do hydrangeas make good cut flowers?
- Why are my zinnias tall and thin with smaller flowers?
- Do I need to stake my zinnias?
- How do I condition my cut zinnia flowers?
- Can I grow zinnias as a houseplant?
- Should I start my zinnias indoors or outdoors?
- How long do sunflowers bloom?
- How many flowers does each stem of the giant sunflowers get?
- Why are my sunflower seeds hollow?
- Are any sunflower seeds toxic?
- What direction do sunflowers face?
- Can I grow Morning Glory in a container?
- Are Morning Glory plants or seeds toxic?
- Why are my Morning Glory plants not blooming?
- Can I start Morning Glory seeds inside?
- What is the difference between seed dahlias and tuberous dahlias?
- Can I start dahlia tubers inside?
- What pollinators do dahlias attract to the garden?
- How do I get the biggest flowers on my dinner plate dahlias?
- Do I need to deadhead my dahlia plants?
- Where should I put cosmos in my flower bed?
- Does cosmos attract beneficial insects to my garden?
- Can I use cosmos as a cut flower?
- Can I start cosmos inside?
- Why hasn’t my cosmos bloomed?
- Can I start my bean plants indoors?
- What is the best region to grow broccoli?
- Why does my broccoli have yellow flowers and no broccoli?
- Why won’t my Romanesco broccoli form a head?
- When should I sow broccoli in the fall?
- Why did my broccoli not form a head or formed a tiny head?
- Can corn be started indoors?
- Why do I have spotty germination on my Sh2 corn?
- Why is my corn leaning over?
- Why don’t my ears of corn have kernels?
- Why did my On Deck corn not produce ears?
- Why is my cucumber have a bitter or poor taste?
- Why do I have lots of leaves but no flowers on my cucumber?
- Why do I have flowers but no fruit on my cucumber?
- Why did my green cucumbers turn yellow?
- Why are my cucumbers curved or deformed?
- Can I hold my garlic until next season?
- Can I plant garlic from the supermarket?
- Why are my tomato leaves curled in on themselves?
- Why is my garlic not bulbing?
- Can I directly eat the garlic I received?
- Can I grow garlic in containers?
- Which type of garlic is best for my growing zone?
- Why did my lettuce seed not germinate?
- Why won’t my iceberg lettuce form a head?
- Why did my lettuce produce a tall stem and flower?
- My lettuce is very bitter (inedible). Why?
- Can I grow lettuce inside or hydroponically?
- How many onions do I get per plant or set?
- Why are my onions not bulbing?
- Can I grow onions over winter?
- How long will my onions store?
- Can any onion be harvested as scallions?
- What is your hottest hot pepper?
- Why is my hot pepper not hot?
- Why is my pepper green and not red?
- Can I grow peppers indoors?
- How are my plants pollinated indoors?
- Do I need divide my mini-tubers into “eyes” before planting?
- Are your mini-tubers certified disease-free?
- How many potatoes do I get from every mini-tuber?
- Do I need to cut off the flowers from my potatoes?
- Can I grow potatoes from the supermarket?
- How many sweet potatoes will I get from every slip?
- Why did I not get any sweet potatoes?
- My sweet potatoes arrived wilted. Are they dead?
- My sweet potatoes have a hollow center in them, why?
- Are the sweet potato vines I see in window boxes edible?
- What are some common tomato diseases?
- What are some common tomato pests and problems?
- Why do I have lots of leaves but no flowers on my tomato?
- Why do I have flowers but no fruit on my tomato?
- Why are my tomatoes malformed?
- How do I grow tomatoes in a really hot climate?
- What could be eating my tomatoes?
- Why does my watermelon have a bitter or poor flavor?
- Why do I have flowers but no fruit on my watermelon?
- Why are there seeds in my seedless watermelon?
- Which seeds are the watermelon pollinator plants?
- What is the difference between a determinate and indeterminate tomato?
- What are good companion plants?
- What are good companion plants for my zucchini?
- Why do my tiny fruit turn brown and fall off my zucchini?
- Why do my zucchini have flowers but no fruit?
- Why does my zucchini have only male flowers?
- How long will winter squash store?
- If my squash is near my pumpkins, will I get mixed fruit?
- Why is my spaghetti squash green and not yellow?
- Why is the center hollow of my watermelon?
- Can I direct sow tomato seeds?
- When should I start my tomato seeds?
- Which seed starting set should I use for my tomato seeds?
- What soil should I use for seed starting?
- Can I use topsoil or garden soil to start my seeds?
- How deep should I plant my tomato seeds?
- How long does it take for the tomato seeds to sprout?
- What is the best temperature to start my tomato seeds?
- Should I use a heat mat with my tomato seeds?
- What is the germination rate of tomatoes?
- Why is the seed stuck to the leaf?
- Should I prune (sucker) my tomato plants?
- Why are the bottom of my tomatoes turning brown?
- Why do my tomato plants have large leaves that don’t look like tomato leaves?
- Can I plant my tomato transplant deeper than they were in the pot?
- What kind of fertilizer should I use on my tomatoes?
- What kind of soil should I use in pots (containers)?
- When do I harvest pumpkins?
- How do I store pumpkins?
- How do I harvest cucumbers?
- What kind of fertilizer should I use on my cucumbers?
- What are some plants that help repel mosquitos?
- Why are my tomatoes cracking?
- What is the difference between summer and winter squash?
- When do I harvest winter squash?
- How do I know when spaghetti squash is ready to harvest?
- How do I store seeds for next year?
- How long does it take for peppers to turn red?
- Why did my lettuce produce a tall stem and flower?
- Are your seeds treated with inoculants?
- Do you carry a soil inoculant?
- What plants can I use soil inoculant on?
- Why are my red peppers green?
- Why do my squash plants have only male flowers?
- How do I prune blackberries?
- How long does it take for my dormant plants to leaf out?
- How far should I plant raspberries from blackberries or wild berries?
- Do I need more than one variety of strawberries to get fruit?
- What is the difference between an annual and a perennial?
- Why is my ‘Nikko Blue’ hydrangea turning pink or purple?
- Why is my ‘Masja’ Pink hydrangea is turning purple or blue?
- How do I tell my corn is ready to harvest?
- How do I harvest corn?
- When is my garlic ready to harvest?
- How do I harvest garlic?
- How do I tell when my cantaloupes are ready to harvest?
- How do I harvest cantaloupes?
- How do I tell my watermelons are ready to harvest?
- How can I know that my onions are ready to harvest?
- How do I harvest and store my onions?
- How do I harvest winter squash?
- My spaghetti squash is green. Is there a problem?
- What plants come back year after year?
- How do I start sunflowers?
- Will my green pepper ripen if it was removed from the plant?
- How do I make my cut flowers last longer in the vase?
- Should I start sunflowers inside?
- What vegetables tolerate being near a walnut tree?
- Why do plants die near a walnut tree?
- What Annual flowers tolerate being near a walnut tree?
- What are pelleted seeds?
- How do I harvest asparagus?
- How do I harvest potatoes?
- What perennial flowers tolerate being near a walnut tree?
- When do I harvest sweet potatoes?
- How do I harvest Sweet Potatoes?
- When are Tomatillo ready to harvest?
- How do you harvest tomatillo?
- Why do my carrots taste soapy?
- Why do my tomatoes have tough skin?
- Why are the tops of my tomatoes remaining green?
- How do you treat your seeds?
- What is the best pH for a vegetable garden?
- What is the best pH for blueberries?
- Do you have any corn that is resistant to corn earworms?
- How do you control cutworms?
- Which garlic should I grow in the fall?
- Which garlic produce scapes?
- Should I remove the flowers from my garlic?
- Are the garlic flowers (scapes) edible?
- How do I reuse a container for next year?
- Can I reuse the potting soil in my containers this year?
- Which side of the seed is up? Does it matter which side it up?
- What does deadheading mean?
- Pests
-
Diseases/Disorders
- Why did my Echinacea flowers turn green and are deformed?
- What flowers are resisitant to Aster Yellows?
- Why is the center of my tomato white or green?
- Why do my tomatoes have a sunken spot on the side?
- What is this white side on my pepper?
- Why does the top of my tomatoes remain yellow (orange)?
- Why is the bottom of my tomato fruit deformed?
- Ask a Question
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Garden Question Library
- Retail Inquiries
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About Burpee
- General Company Questions
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Customer Service FAQs
- Do you have blank order forms?
- When do you switch to the next seasons' seed?
- What methods of payment do you accept?
- Can you ship your products internationally?
- Can you provide a phytosanitary certificate?
- Can I preorder a “currently unavailable” item?
- Where can I find my zone?
- What is restricted to my state?
- What are your product guarantees?
- How do I get a refund or replacement for my damages product?
- How can I return my order?
- When will your fall plants be shipping?
- How can I request a catalog?
- How can I place an order?
- How can I check my ticket status?
- Does your company offer donations?
- Do you ship to Canada?
- Do you sell GMO or Round Up ready seeds?
- Can I change the shipping date for my plants?
- Are you owned by Monsanto?
Related Articles
- Why is my 'Big Mama' tomato leaves curled?
- Are the tires of the Ultimate Gardener Cart (99103) pneumatic?
- Where is Sea Magic manufactured?
- What is Sea Magic (99004) made from?
- Do you have the directions for Sea Magic 99004?
- Do you have any self-pollinating cucumbers?
- What are some plants that tolerate rocky soil?
- Will the 12 in 1 garden bed get too hot in the summer or in hot climates?
- What are the assembly instructions for the 17" Tall 42" Round galvanized garden bed?
- What comes with the Worm Factory 360?
- What are the dimensions of the Adjustable Frost Protection Kit (99968)?
- When do I havest beans?
- What kind of support do beans need?
- When is the best time to plant beans?
- Can I get more information on the Crimson Star Goji Berry (22311)?
- Do you have the instruction for how to use the Burpee Enhanced All Purpose 5-5-5 plant food?
- Do you have the instructions on how to use Burpee Enhanced Tomato + Edibles 8-4-4?
- My kohlrabi did not form a bulb can I still eat the plant?
- Why does the kohlrabi bulb taste hot?
- Why is the kohlrabi bulb cracking?
- Why is my kohlrabi bulb woody?
- Do you have instructions on the Deluxe LED Glow-N-Grow Light Kit?
- Do you carry Cucamelon seeds?
- How long does it take to see the potato plants grow?
- What is the difference between male and female cucumber flowers?
- What were some common Kitchen Garden Vegetables from the early 1900's?
- Do I need two varieties of figs to get fruit?
- Why are my carrots pale yellow?
- How deep does a pot need to be to grow carrots?
- Why do my stored carrots taste bitter?