There are many good seed and garden supply companies. Many of them have catalogs that are excellent sources of general gardening information as well as sources for mail order seeds and supplies The internet has also become a rich source for gardening information and supplies. Below are some companies listed alphabetically, that I have found useful or interesting. No slight is intended to the many good companies not mentioned.
The non-North American listings are especially limited, but may be a useful starting place looking for seeds of specific tropical plants. Many of the seed sources listed here deal mainly with very small packets of seeds. There are numerous rules restricting the movement of seeds between countries. You may need to get a phytosanitary document, declaring the seed to be free of pathogens, like viruses, from the seed source. Find out about this before ordering seeds or they may be confiscated.
North American
Abundant Life Seed Foundation
P.O. Box 772
Port Townsend, WA 98368
(360) 385-5660 (seeds -- OP varieties only; many heirlooms; most seeds certified organic; non-profit organization) catalog
Brooklyn Botanic Garden Seed and Plant Sources
The Cook's Garden
P.O. Box 535
Londonderry, VT 05148
(802) 824-3400
(seeds -- OP and hybrid varieties, including many European short-season regions)
Early's Farm and Garden Centre
2615 Lorne Avenue
Saskatoon, SK S7J 0S5
Canada
(306) 931-1982
(seeds -- hybrids and OPs, including varieties for cold, short-season regions)
catalog
ECHO
17391 Durrance Road
N. Fort Myers, FL 33917 - 2239
(941) 543 3246
Fedco Seeds
P.O. Box 520
Waterville, ME 04903
(207) 873-7333 (seeds -- large collection of hybrids and OPs, including many heirlooms; seed cooperative) catalog
Gardener's Supply Company
128 Intervale Road
Burlington, Vermont 05401-2850
(800) 863-1700
Haitai Seeds
AgroHaitai Ltd.
PO Box 45
Lynden, Ontario L0R 1T0
Canada
Excellent source for Asian vegetable seeds
Harris Seeds
P.O. Box 22960
Rochester, NY 14692-2960
(716) 442-0410
(seeds -- wide selection, including many proprietary hybrids with improved disease resistance)
catalog
Heirloom Seeds
P.O. Box 245
West Elizabeth, PA 15088-0245
(412) 384-7816
(seeds -- OP heirloom varieties only)
catalog
J.W. Jung Seed Co.
335 South High St.
Randolph, WI 53957
(414) 326-3121
(seeds -- OP and hybrid varieties, many selected for northern gardeners)
catalog
Johnny's Selected Seeds
310 Foss Hill Road
Albion, ME 04910-9731
(207) 437-9294
(seeds -- large selection of Open Pollinated and hybrids for northern regions; greenhouse varieties)
catalog
Liberty Seed Company
P.O. Box 806
New Philadelphia, OH 44663-0806
(330) 364-1611
(seeds -- good collection of hybrid and OP varieties chosen for the Midwest)
catalog
Morgan County Seeds
18761 Kelsay Road
Barnett, MO 65011-3009
Inexpensive basic garden seeds
The Natural Gardening Company
217 San Anselmo Avenue
San Anselmo, CA 94960
(415) 456-5060
(plants -- selection of heirloom and other choice varieties;organically grown)
catalog
Park Seed Co.
P.O. Box 31
Greenwood, SC 29647-0001
(864) 223-7333
(seeds -- mainly hybrid varieties, including many bred for the South)
catalog
Peaceful Valley Farm Supply
P.O. Box 2209
Grass Valley, CA 95945 (530) 272-4769 Fax: (530) 272-4794
Peters Seed & Research
407 Maranatha Lane
Myrtle Creek, OR 97457
(541) 863-3693
(seeds -- large collection of unusual OP varieties)
catalog
Pinetree Garden Seeds
P.O. Box 300
New Gloucester, ME 04260
(207) 926-3400
(seeds -- good selection of hybrid and OP varieties for the home gardener)
catalog
R.H. Shumway's
P.O. Box 1
Graniteville, SC 29829
(803) 663-3084
(seeds -- OP and hybrid varieties, including many older home-garden favorites)
catalog
Seed Savers Exchange
3076 North Winn Road
Decorah, IA 52101
(319) 382-5990
(seeds -- membership gives access to largest collection of OP varieties available to gardeners; nonprofit organization)
membership
Seeds of Change
P.O. Box 15700
Santa Fe, NM 87506-5700
(505) 438-8080
(seeds -- good collection of OP and heirloom tomatoes, especially for the Southwest; organically grown seed)
catalog
Seeds Trust-High Altitude Gardens
P.O. Box 1048
Hailey, ID 83333
(208) 788-4363
(seeds -- tomatoes for short, cold seasons, including many Russian imports)
catalog
Shepherd's Garden Seeds
6116 Highway 9
Felton, CA 95018
(408) 335-6910
(seeds -- international collection of OP and hybrid tomatoes chosen for flavor)
catalog
Southern Exposure Seed Exchange
P.O. Box 170
Earlysville, VA 22936
(804) 973-4703
(seeds -- heirloom and OP varieties, many adapted for southern gardens) catalog
Stokes Seeds Inc.
Box 548
Buffalo, NY 14240-0548
(716) 695-6980
(seeds -- large, superb collection of hybrids and OPs for home and market gardeners)
catalog
Territorial Seed Company
P.O. Box 157
Cottage Grove, OR 97424
(541) 942-9547
(seeds -- wide selection of OP and hybrid tomatoes, including many chosen for
short seasons)
catalog
Otis S Twilley Seed Co., Inc.
121 Gary Rd.
Hodges, SC 29653
(800) 622-7333
Fax: (864) 227-5108
Email: twilley@twilleyseed.com
Website: www.twilleyseed.com
(large collection of hybrid tomatoes, including many market varieties)
catalog
Vesey's Seeds Ltd.
P.O. Box 9000
Calais, ME 04619-6102
(902) 368-7333
(varieties for short, cool seasons)
catalog
W. Atlee Burpee & Co.
300 Park Avenue
Warminster, PA 18974
(800) 888-1447
(seeds -- good selection of varieties, including many Burpee introductions)
catalog
Non-North American
B &T Associates
Whitnell House
Fiddington
Bridgewater
Somerset TA5 1JE
United Kingdom
tel: 278 733 209
Chambers Seeds
5 Westleigh Rd.
Barton Seagraves
Kettering
Northants NN15 5AJ
UNITED KINGDOM
tel: 0933 681 632
Chitern Seeds
Bortree Stile
Ulverston
CumbriaLA12 7PB
UNITED KINGDOM
tel: 0229 581 137
Dumon Agro NV
Pathoekeweg 40
8000 Brugge
BELGIUM
tel: 32 050 315161
fax 050 315171
fax 050 315171
(large quantities only)
Eden Seeds
MS 316
Gympie 4570
AUSTRALIA
tel: 071 86 5230
Empresa de Semillas Forrajeres
Casilla 593
Tiquipaya
Cochabamba
BOLIVIA
tel: 41975
Gunson Seed
Nature Rd
Zesfontein 7409
Petit 1512
REPUBLIC OF SOUTH AFRICA
Inland and Foreign Trading Co., Ltd.
Block 79A
Indus Rd. # 04-418/420
SINGAPORE 0316
tel: 272 2711 or 278 2193
Kenya Seed Co.
Elgon Downs Farm Research Centre
PO Box 13
Endebess
KENYA
tel: 0325 20941 (42 & 43)
Kumar International
Ajitmal 206121
Etawah
Uttar Pradesh
INDIA
Phoenix Seeds
PO Box 9
Stanley
Tasmania 7331
AUSTRALIA
tel: 00458 1105
Pocha Seeds Pvt. Ltd.
PO Box 55
Near Sholopur Bazaar
Poona 411 040
INDIA
tel: 671978
Primac Seeds
PO Box 943
Murwillumbah
NSW 2484
AUSTRALIA
tel: 6166 72 1866
Queensland Agricultural Seeds Pty.,Ltd.
PO Box 1052
Toowoomba, QLD 4350
AUSTRALIA
tel: 61 76 30 1000
Setropa Seeds
Troelstralaan 4
1272 JZ Huizen
HOLLAND
Sutton and Sons, (INDIA) Pvt. Ltd.
PO Box 9207
Calcutta 700 071
INDIA
tel: 91 3329 0472
T.S.L. Ltd.
PO Box 66043
Kopje
Harare
ZIMBABWE
tel: 68685 94; fax: 68698
Tokita Seed Co., Ltd.
Nakagawa
Omi ya-shi
Saitama-ken 330
JAPAN
tel: 048 683 3434